Porsche Boxster Common Problems

Symptom: Oil Leak Between Engine & Transmission Joint

One of the most common, misunderstood and potentially destructive issues on the Boxster,  is an oil leak from the rear main seal. A leaking rear main seal appears through the bell housing joint between the center of the engine and transmission joint. The leaking seal will quickly destroy a clutch in a manual car if not addressed promptly and can be a sign of other issues.

Some caution – vehicles that are stored often display a weep/leak from the seal during storage or at the initial startup in the spring. The seal needs the heat of driving to remain sealed efficiently, so in some circumstances the leak can slowdown or stop during the driving season. Replacing the seal requires the removal of the transmission and in a manual car, replacement of the clutch at the same time is a good choice.

The seal does dry over time and can leak, however, there are other potential issues that could also cause the seal to leak (see Air Oil Separator below). Causes of the seal failure should be checked thoroughly by a competent shop before you proceed to replace the seal.

Porsche Boxsters have a number of common sources for leaking oil.  Some of the most common include rear main seal (see below), valve covers, spark plug seals and oil cooler seals. Less common are leaks from the cam seals and scavenger oil pump seal.

Symptom: Oil Drips on Floor Below Engine

Valve cover leaks are obvious and fairly straightforward to fix on most models. The valve covers do not have a gasket – instead a liquid gasket sealer is used. The time consuming part is removing the old gasket sealer from the valve cover to ensure a good seal for the replacement. Valve cover leaks can make their way onto the exhaust headers and lead to a burning smell or worse.

Symptom : Misfires CEL or Oily Spark Plugs

Spark plug tube seals are also prone to leaking – leaks from the spark plug tube seals can be frustrating. Often, you wont see the oil initially, as it’s sealed in by the coil on top of the spark plug. The tube fills with oil and causes misfires by destroying the plug and the coil. If you see oil on a plug or coil, always replace the seals.

The upper seal can be replaced when removing the valve cover.  The lower seal leaking is less common but more of an issue and requires removal of the camshafts.

Oil Drain Plug Leak

This should really never happen and is usually the result of a failure to replace the drain plug or its seal.

Symptoms : Smoke From Exhaust, Oil In Intake, Rear Main Seal Leak

Bad rear main seal or something else causing the problem?

An integral part of the emissions system, the Air Oil Separator (AOS) is designed to extract oil from gases in the crankcase. The oil is recycled to the sump, while the gas is passed through the combustion path to be burnt and cleaned by the catalytic converters. The AOS has caused numerous issues on Porsche engines and is an item to be closely monitored.

As the membrane in the AOS fails, oil is sucked into the air intake. Initially this can show up as a check engine light for fuel adaptations with oil being deposited on the o2 sensors causing emission faults.

Of course, once it fails completely, the resultant burning oil produces huge clouds of white smoke – this is fairly obvious. At that point, it is clear what needs to be done.  However, replacing the aos sooner rather than later can be a good precaution against other failures.

A failing air oil separator (aos) is the likely cause of rear main seal failure and oil leaks, as it is in other VAG cars. Crankcase vacuum exceeds the normal range in the engine under heavy acceleration and sucks in air damaging the rear main seal. This is commonly seen on Audi engines as well.

A failing aos also causes too much oil to pass into the intake and will force the engine management to adjust fuel mixtures to compensate. The changing mixture can cause over fueling and lead to other more significant problems – See smoke at startup below.

For cars that go to the track on a regular basis, a Porsche Motorsport AOS upgrade is highly recommended. The upgraded aos features a doubling in size of capacity for scavenging and is less prone to sucking up oil during high speed cornering.

A quick puff of smoke as you start a cold engine is not uncommon, especially on the Porsche flat six engine in the Boxster. There are many theories and various thoughts as to why this happens – none are proven. What is known, is that re-built engines rarely display this startup smoke, so it’s definitely a sign of wear and tear – and it does progressively get worse with mileage. Vehicles that have sat for a while, such as winter storage for example, often blow more smoke at their first start rather than subsequent ones.

Extended smoking at startup is more of an issue. Again, there could be a number of reasons why this happens, but it is usually a sign of wear in the cylinders. See cylinder scoring below.

Sometimes, replacing the fuel injectors can help this problem. Worn and leaking fuel injectors cause fuel to sit in the intake path while the car is parked. The fuel leaking is not enough to cause starting problems, but it can be responsible for the smoke and wear in the cylinders – the excessive fuel heading into the cylinders washes oil off the cylinder walls causing wear on the piston rings and liners. The burning oil / fuel mixture makes more smoke.

The smoke at startup can also be caused by a bad air oil separator (AOS) that has not completely failed yet.

Symptoms: Metallic Debris in Oil, Unusual Engine Noises, Potential Engine Failure

The M96 and M97 engines fitted to the Porsche Boxster 986 and early 987 models use an intermediate shaft (IMS) to drive the engine camshafts. A sealed bearing supports one end of this shaft and can deteriorate, potentially causing significant internal engine damage if it fails.

There is no doubt that the original IMS bearing is a known weakness in these engines. However, the amount of publicity surrounding IMS failures can give owners the impression that every early Boxster will eventually experience catastrophic engine failure. That simply isn’t the case.

IMS Bearing Risk Varies by Model Year

Early 986 engines generally used a stronger dual-row bearing, while many 2000–2005 models used a smaller single-row bearing associated with a higher failure rate. Porsche introduced a larger, more robust bearing during the 2005 transition, fitted to all 2006–2008 Boxster models. However, this later bearing cannot be replaced without significant engine disassembly.

The redesigned 987.2 engines introduced for the 2009 model year eliminated the intermediate shaft and IMS bearing entirely. Consequently, the 981 and 718 generations do not suffer from this particular problem.

Should You Replace the IMS Bearing?

For engines fitted with the earlier serviceable bearings, preventative replacement is generally recommended, particularly when the transmission is already removed for clutch or rear main seal work. A properly documented bearing upgrade can also provide reassurance to potential buyers and help maintain the value of the car.

The larger bearing fitted to 2006 – 2008 models presents a different situation because replacement requires engine disassembly. An experienced Porsche specialist should assess the engine and recommend the appropriate approach rather than automatically suggesting bearing replacement.

Regular oil changes, inspection of the oil filter for metallic debris and attention to unusual mechanical noises are sensible precautions. However, bearing deterioration may occur without obvious warning signs.

The Bottom Line

IMS bearing failure is a genuine concern for certain early Boxster engines, but it should not automatically discourage ownership or the purchase of an otherwise well-maintained car. Understanding the specific engine, bearing design and maintenance history is far more useful than treating every Boxster as equally vulnerable.

Symptoms: Engine Knocking Noise, Oil Consumption, Black Exhaust Tail Pipe

The M96 and M97 Porsche engines are famed for cylinder bore scoring – deep gauges in the cylinder liner, usually associated with a knocking noise, excessive oil consumption, and eventually catastrophic engine failure.

Bore Scoring Problems

The most consistent and common cause of bore scoring is poor lubrication. When the oil film between the piston rings and cylinder wall breaks down, metal parts make contact causing the piston to wobble. The wobble occurs on the thrust side of the stroke and results in the piston skirt dragging against the cylinder walls. The result is deep grooves in the cylinder liner referred to as bore scoring. This leads to excessive oil consumption, loss of performance, and eventually a nasty knocking noise and engine failure.

Bore scoring is a problem that requires a full engine rebuild.

Identifying Bore Scoring – Scoping the Cylinders

Most people are aware of the recommendation to scope the cylinders with a camera. However, the camera typically makes marks in the cylinder look considerably worse than they are. What can often be seen is vertical markings in the cylinders of various shades of grey. This is typical of Porsche engines and the result of poor oil film protection from petroleum-based oils (as described below). A bore score is a deep grove that you can feel with your finger and typically shows up as a bright silver reflective mark with the camera. Bore scoring can easily be misdiagnosed – the image of the liner here shows wear and not bore scoring. Whereas the image of the piston shows clear signs of bore scoring.

The grey marks running up and down the cylinder liner are telltale signs of wear – however, they are not necessarily bore scoring. Scoring is best seen with a camera through the sparkplug hole – roughly 80% of the problem can be seen this way. The balance of the scoring is visible by removing the oil pan and viewing from below.

External Bore Scoring Indicators

A badly scored engine will develop a nasty knocking noise. The sound of this problem is not a tick like a bad lifter; it’s more a rhythmic knock and usually shows up first on the passenger bank of the flat 6 engines. The rhythmic knock is the piston changing position at the bottom or top of the stroke and hitting the liner.

Black Soot Deposits on Exhaust Pipes

One of the potential early signs of significant engine problems is a mismatch in the sooty deposits inside the exhaust tailpipes – one side with more black carbon than the other. This can also be accompanied by smoke from the exhaust at cold start. These signs usually show a difference in the running efficiency of one bank of cylinders versus the other and further investigation into the cause is necessary.

Oil Consumption

The integrity of the piston ring to cylinder liner interface is likely the most important factor in engine oil consumption. Wear in the ring to liner interface causes oil to pass into the combustion chamber and leads to high oil consumption.

Fixing Bore Scoring

The only fix for bore scoring in a Porsche engine is a full engine rebuild. Costs to rebuild most Porsche engines are north of $25K.

Preventing Bore Scoring

Porsche engines are high performance and feature a tight fit between piston and cylinder liner. The integrity of the interface between piston rings and liner, wear on the rings, and piston ring groove widening control, is therefore critical to the long-term health of a Porsche engine.

It should be obvious that the piston ring to cylinder liner interface is the responsibility of oil. Clearly, the petroleum-based synthetic oils used in Porsche engines have failed to adequately maintain the integrity of the piston ring to cylinder liner interface. This is why we recommend Evolve Oil. Porsche tests prove that Evolve oil better protects the piston ring to cylinder liner interface.

Symptom: Rattle Under Acceleration, Power Loss, CEL

This is a common issue on the older Boxster engines.  A recurring check engine light under acceleration is the first sign. Subsequently, an engine rattle at startup or under acceleration becomes more prevalent and a CEL sets consistently.

Porsche Boxster Stretched Timing Chain

The typical cause of this problem is a stretching of the timing chains and failure of the timing chain tensioner. The only solution is to replace the tensioner and the timing chains. Porsche updated the timing chain tensioners to help eliminate this problem going forward.

This is an expensive job that requires engine removal and the right timing tools necessary to complete the work.

Find a local shop that can do the work for you.

Symptoms: Check Engine Light, Engine Runs Well, No Loss of Power

There are many potential causes of a Check Engine Light on the Porsche Boxster and it’s important to read the engine codes or have a repair shop do that for you to assess the faults. Typically, an engine that sets faults yet runs well, suggests problems related to emissions control.

Older M96 Engine Faults

One of the most common causes for a CEL on the older M96 engine in the Boxster is a failure in the O2 sensor and mass airflow systems (MAF). Commonly, the MAF begins to fail and delivers the engine management with inaccurate information regarding the flow of air into the intake.

This causes the engine management to adjust fuel mixtures using a set of parameters which were likely set too broadly by Porsche initially. The resultant adjustments cause the front O2 sensors to report faults and often lead to them failing completely. The fault codes will suggest faulty O2 sensors. This results in many folks just replacing the front O2 sensors in the hopes of solving the problem, only to discover that within a few hundred miles, the check engine light is back on.

Mass Air Flow Sensor Fault

The problem is actually caused by the MAF failing and by owners blindly believing the reported engine faults. The faults are an indication of the symptoms and not the route cause. The recommended solution is to replace both the MAF and front O2 sensors at the same time. Always use the original Porsche parts – the aftermarket versions do not work. Cleaning the MAF rarely fixes this problem.

Symptoms : Engine Runs Rough or Lacks Power – Flashing CEL

Misfires can occur at any time on the Boxster engine and require diagnosis to identify which cylinders are misfiring and why. Common causes are worn spark plugs, cracks in ignition coils and oil leaking past the spark plug tube seals.

The ignition coils on the M96 and M97 Boxster engines have been updated by Porsche multiple times. The original coils were prone to cracking and were replaced by a more substantial version. Low mileage older cars will commonly still have the older style coils and it’s best practice to replace them all to the newer version, even if only a single coil has failed.

Fuel Injector Malfunction

Fuel injector malfunction can cause a misfire, however injector failure of this nature is not so common on the Porsche flat 6 engines – even the older versions. More commonly, a failure in the wire or plug connected to the injector can cause a weak of misfiring cylinder. These wires and connectors can become brittle and crack, especially when being moved around for routine maintenance. Check the wiring thoroughly before replacing injectors.

High Pressure Fuel Pump Failure

On the later Boxster engines equipped with direct fuel injection, starting with the 987.2 3.4L, a failing high-pressure fuel pump can also cause misfires and rough engine running.

Symptoms : Engine Runs Well Up To 4K RPM then Misfires

This is a problem that many so-called experts will tell you doesn’t exist. However, we have diagnosed and fixed this issue on a number of Boxster engines.

If you have the issues, you find the engine runs perfectly below 3K rpm. Revving the engine above 4K rpm causes a misfire to be reported on a single cylinder and engine management shuts off the cylinder. Consequently, below 3K rpm the engine now runs rough until the fault is cleared. Once the fault is cleared the engine runs perfectly again below 4K until the fault is triggered again.

Typically, this happens to a single cylinder repeatedly. Initially, this sounds like a failing spark plug, injector or coil and can indeed be solved by replacing them, if you’re lucky. However, if you have replaced both the coil and the plug and still have the same problem, there is another solution.

Intake Valve Lifter Problem on Porsche Engines

The Porsche flat 6 engine (in particular the M96) has a two-stage intake lifter that fails. As you accelerate the engine rpm, the lifter expands to increase valve lift. The lifter commonly breaks and during the second stage of valve lift, which occurs above 4k rpm, it does not function correctly – this results in a misfire on a single cylinder.  The engine management then shuts off the cylinder until the fault is cleared.

This problem can be solved by replacing the lifters on the particular cylinder on which the fault occurs – although replacing all the lifters on that particular bank, whilst expensive, is probably the recommended solution. If left alone, the lifter can stick causing a permanent misfire or worse.

In a couple of customer cases that we’ve seen, the stuck lifter went on to break the intake camshaft destroying the bearings in the valve cover. We also experienced a Boxster engine where the lifter had been ejected out of the valve cover, leaving a nicely sized hole and very oily mess. In both these cases the engines were repaired and functioned perfectly afterwards.

Replacing lifters requires specialized skills and timing knowledge – we recommend you seek the help of an independent repair shop.

The direct fuel injection engines on the later Boxster models can experience carbon buildup in the intake path. Carbon deposits on the intake valves and chamber area can restrict the flow of air to the cylinders. This causes a lack of power, rough idle, increased fuel consumption, and hesitation under acceleration. There are several cleaning processes available from independent shops to remove the carbon build-up.

Symptoms : Check Engine Light and Lack of Power

The M96 and M97 engines found in the Boxster have variable valve lift and timing. Part of the variance is controlled by the cam solenoids located in the valve covers. The cam solenoid is an electro-mechnical device that redirects oil pressure as per the demands of engine management. The increase in oil pressure enables valve lift adjustment.

Cam Solenoid Failure Porsche Engine

Problems with these solenoids are often the cause of a CEL and a lack of power under acceleration. Scanning the engine management system should provide fault codes which identify the solenoids that are failing. Replacing them usually solves the problem.

Some of the cam solenoids can be replaced without the removal of the valve cover; however, others do require the valve cover removal and are more intense work especially on the Boxster. We recommend inspection of the wiring to the solenoids before replacing them – these can become corroded on older cars due to their location.

Symptoms: Broken Spark Plug, Misfires, CEL

his is a problem that is simple to prevent but often overlooked. Older, low mileage Boxsters regularly still have their original spark plugs. Porsche’s recommended replacement intervals vary by engine and model year, with earlier 986 models originally having intervals as long as 60K miles or 6 years, while many later naturally aspirated models use shorter intervals and turbocharged 718 models typically require replacement at 30K miles or 3 years.

However, with many Boxsters being used as low mileage weekend cars, the mileage intervals for spark plug replacement are often never reached.

Plugs that have been in the engine for more than 10 years can be very difficult, if not impossible, to remove. A stuck or broken plug in the cylinder head is an expensive problem to solve and one that can be simply avoided.

We recommend checking when the plugs were last changed rather than simply looking at the mileage. For older, low mileage cars, changing the plugs every 4 or 5 years seems like a sensible precaution to us. Why risk an expensive repair to save the cost of a few spark plugs?

Symptoms: Engine Stumbles, Misfires, Loss of Power, Poor Acceleration, CEL

The later Porsche Boxster direct fuel injection engines feature a high-pressure fuel pump driven from a camshaft. This includes the 987.2 3.4L, the 981 and the later 718 engines. The 987.2 2.9L uses a different fuel injection system and does not have the same high-pressure pump.

The high-pressure fuel pump can fail, typically causing a check engine light and fault codes associated with low fuel rail pressure. Common symptoms include:

• Delayed engine starting or extended cranking
• Hesitation or sputtering under acceleration
• Loss of power and poor acceleration
• Random engine misfires
• Engine stalling or difficulty restarting

The good news is that replacing a failed high-pressure fuel pump is relatively straightforward compared with many other Porsche engine repairs.

However, don’t be too quick to condemn the pump. A failing in-tank fuel pump, fuel pressure sensor or electrical problem can produce very similar symptoms. This seems like a good opportunity to replace the expensive high-pressure pump until you realize it isn’t receiving enough fuel from the tank in the first place!

We recommend checking both the low-pressure fuel supply and high-pressure system before replacing anything. The fault codes tell you where to start looking, not necessarily which part to replace.

Symptoms: Check Engine Light, Oxygen Sensor Fault Codes, Poor Fuel Economy, Rough Running

The 2017 Porsche 718 Boxster and Boxster S feature oxygen sensors that monitor the exhaust gases and help the engine management system maintain the correct fuel mixture. Unfortunately, these sensors can fail, causing a check engine light and a collection of engine management fault codes.

The upstream oxygen sensor is located before the catalytic converter and plays an important role in controlling the engine’s air/fuel mixture. A failing sensor can provide inaccurate information to the engine management system, potentially resulting in poor fuel economy, hesitation, rough running or increased emissions.

Of course, an oxygen sensor fault code doesn’t automatically mean the sensor has failed. Exhaust leaks, wiring problems and incorrect fuel mixtures can produce similar symptoms. Replacing the sensor without checking the actual cause could be an expensive mistake.

Porsche Oxygen Sensor Warranty Extension – 2017 Boxster

Porsche introduced an extended warranty for the upstream oxygen sensor on eligible 2017 718 Boxster and Boxster S models. Under Porsche Technical Information 22/21, the warranty was extended to 10 years from the original vehicle delivery date or 150,000 miles, whichever comes first. The extension applies to eligible vehicles in the USA, Canada and Puerto Rico and automatically transfers to subsequent owners.

That’s considerably longer than the normal new vehicle warranty, and certainly worth knowing about before paying for a replacement sensor! The coverage is specifically for the oxygen sensor located upstream of the catalytic converter. It is not a blanket warranty for all oxygen sensors, catalytic converters or other engine management components.

Does Your 718 Qualify?

If your 2017 Boxster develops an oxygen sensor fault, ask an authorized Porsche Center to check the VIN and available warranty coverage before authorizing repairs. Porsche records the extended coverage in its Central Service System under “Ext. Warranty Oxygen Sensor.”

The exact warranty expiration depends on the original vehicle delivery date, so not every 2017 model will have the same remaining coverage. We recommend confirming the diagnosed fault and checking the extended warranty before replacing the sensor. There’s no point paying for something Porsche may already be responsible for!

Symptoms: Warning Message Oil Level Too Low or High

If you experience an oil level too high or too low message, be careful. First, there is no dipstick – brilliant idea most of the German car manufacturers have implemented. The oil level is measured electronically for accuracy. This is awesome, assuming the electronic measurement is accurate or is at the very least telling you the truth. There is no manual backup of the tried and trusted dipstick – so did you overfill or under fill? Or do you have a faulty sensor?

Is The Oil Level Sensor Telling The Truth?

You have to be sure of which one before you take action. The only way to be sure is confirm the amount of oil in the engine by draining and measuring. We’ve experienced an oil reading that went down when we added a quart!

Don’t be surprised if the oil level sensor is not telling the truth but, make sure you are certain that the oil level is correct before ignoring the sensor and replacing it.

Oil Level Top Off

The Porsche turbo engines will naturally consume oil while you drive. Different driving styles and conditions will cause oil consumption to change. With the extended mileage between oil changes that manufacturers have opted for, it’s very likely the car will call for additional oil between scheduled service intervals. Most independent shops consider the extended mileage range between oil changes too extreme and simply a marketing gimmick.

If your Boxster calls for additional oil, here’s what to do:

• Ideally, the engine should be at operating temperature
• The difference between the min and max reading is approx. 1 quart
• Do not add more than 1 quart at a time
• Remeasure the oil level after each quart added
• After adding a quart, drive the car for 5 mins before rechecking
• Oil reading is not instant and requires a drive cycle

Diagnostic Computer Required For Oil Fill

The latest cars require the use of the PIWIS to correctly fill the oil level. This is an extended process that requires connecting the PIWIS and perform an oil measurement procedure with the engine running. The system will then conduct an oil measurement when the recommended engine temperature is reached. The PIWIS will then recommend the amount of oil needed to complete the refill.

Unfortunately, this process can take quite a while and may need to be repeated several times to accurately set the correct oil level.

The problem of high oil consumption affected a good number of early engines in the 987.2 Boxster. Typically, this resulted in the consumption of a quart of oil every 1K miles driven. In the most severe cases the engine was replaced under warranty. Low mileage versions of the early 987.2 may not have identified this engine issue. Check the soot on the tail pipes and the average fuel consumption shown on the dash. More soot and increased fuel consumption may be signs of oil consumption. Changing oil can help – petroleum-based synthetic oils are more likely to be consumed and degrade quickly. Switching to a renewable oil may help with oil consumption.

The later Boxster engine features a hydraulic belt tensioner that has a life span of about 60K miles or 6 years. The telltale sign of impending failure is rust on the bolt that holds the tensioner to the engine. Hydraulic fluid leaks out, the tension is lost, and the bolt head rusts. Tension on the belt is critical for driving the water pump, AC compressor etc. and a correctly tensioned belt is a critical engine component. You can often see the belt wobble or hear a knocking sound on cold start.

The tensioner has been update a number of times and this work should be evident in the history of the pre-owned Boxster you plan to buy. If there is no history of this work plan to replace the tensioner and preempt the problem.

Early Boxster versions with the turbo engine experienced issues with the the turbo wastegate actuator that can develop excess play and movement causing a metallic rattle sound. This is usually prevalent during cold start conditions but gets worse with age. The turbo was subsequently updated to eliminate this issue and many of the units replaced under warranty. Early low mileage 982 Boxster 718 models should have the turbo closely inspected and examine the history to see if this repair was completed under warranty. Replacing the turbo is not cheap and is likely needed on an earlier car with no history of the work being completed.

Many Boxster models are starting to experience failure of their catalytic converters and mufflers. In many cases, the main exhaust header pipe leading to the cat converter will crack and fail completely.

Exhaust Rattle and Muffler Failure

Initially, you’ll start to notice a rattle back there. This is caused by the muffler, the cat or both coming apart internally. While annoying, it’s also potentially destructive – a partial blockage in the exhaust can cause the engine to not run or worse, it will cause immense heat to build at the blockage point. Seeing a catalytic converter glowing bright orange under the bumper of a Boxster is quite disconcerting! This has car fire written all over it!

The disintegration of the catalytic converter typically causes a check engine light with emission fault codes associated to converter inefficiency. This means you can’t pass the emissions test and in some states that means not driving the car at all.

Symptoms: Ticking Noise, Exhaust Rattle, Exhaust Smell, Increased Engine Noise, Check Engine Light

Exhaust leaks are common on older Porsche Boxster models, particularly the 986 and 987 generations. The exhaust system is exposed to considerable heat, moisture and road debris, so it’s hardly surprising that components eventually deteriorate.

Cracked exhaust manifolds, leaking gaskets and corroded exhaust flange connections can all produce similar symptoms. Often the first sign is a ticking or blowing noise when the engine is cold that becomes less noticeable as the exhaust heats up and expands. The problem can be relatively straightforward to identify. Unfortunately, fixing it isn’t always quite so simple!

Corroded Exhaust Bolts and Broken Studs

One of the biggest headaches on older Boxster models is the condition of the exhaust manifold bolts and flange connections. The steel fasteners are exposed to years of heat cycles and corrosion, and those threaded into the aluminum cylinder heads can become extremely difficult to remove. Broken manifold bolts can require specialist drilling equipment, considerable patience and sometimes thread repairs to the cylinder head. Suddenly, a relatively inexpensive exhaust leak becomes a much bigger job.

We recommend inspecting the condition of the exhaust fasteners before estimating repairs. An experienced Porsche specialist will know when to carefully work a stubborn bolt loose and when it’s better to prepare for extraction.

Exhaust Rattles and Catalytic Converter Problems

Rattling noises can also develop from loose heat shields, damaged exhaust brackets, internal muffler components or deteriorating catalytic converters.

A failing catalytic converter can produce a metallic rattle, reduced performance or a check engine light with catalyst efficiency faults such as P0420 or P0430. However, don’t be too quick to blame the catalytic converter. A loose heat shield can sound remarkably similar, and catalyst efficiency faults can have several causes, including exhaust leaks, oxygen sensor problems and incorrect fuel mixtures.

We recommend checking the complete exhaust system, identifying any leaks and confirming the source of the noise before replacing components. Pay particular attention to the condition of the exhaust fasteners on older cars.

Symptoms: Exhaust Sound Doesn’t Change, Rattling Exhaust, Stuck Exhaust Valves, Unusual Exhaust Noise

The optional Porsche Sports Exhaust system, commonly referred to as PSE, is a popular feature on the Boxster. It’s designed to change the exhaust sound by opening and closing valves within the exhaust system. Press the sports exhaust button and the car should produce a more aggressive exhaust note. Simple enough, or so you would think!

Unfortunately, the exhaust valves and their operating mechanisms can develop problems, particularly as the car ages. These issues are familiar on the 981 and 718 models, although earlier Boxster models fitted with a valved sports exhaust can suffer similar failures.

The exhaust valves operate using vacuum-controlled actuators on many versions of the system. A control solenoid directs vacuum to the actuators, opening or closing the valves as required. Over time, the valve shafts and linkages can become stiff or seize completely. The vacuum actuators can also fail, while damaged vacuum lines or a faulty control solenoid can prevent the valves from operating correctly.

The result is an exhaust that remains permanently loud, doesn’t become louder when the button is pressed, or produces an annoying rattle at certain engine speeds.

Diagnosing Porsche Sports Exhaust Problems

Start by checking whether the exhaust valves actually move when the system is operated. On many vacuum-controlled PSE systems, the valves are normally open without vacuum and close when vacuum is applied.

If the valves are stuck, inspect the external linkages and valve shafts for corrosion or mechanical damage. If the mechanism moves freely, check the vacuum supply, actuator diaphragms, hoses and control solenoid. One important point is that a problem with the vacuum supply doesn’t necessarily mean the exhaust itself has failed. On some Boxster models, the PSE shares parts of its vacuum system with other engine controls, so vacuum leaks can produce additional symptoms or warning messages.

Repair or Replace the Complete Sports Exhaust?

Here’s where things can get expensive. Depending on the design and the failed component, Porsche’s replacement solution may involve fitting a complete muffler assembly. This can be expensive when the muffler itself is perfectly healthy and the problem is a stuck valve, damaged vacuum line or failed actuator!

In some cases, the mechanism can be freed up or the faulty control component replaced without requiring a complete exhaust. However, badly corroded valve shafts or damaged internal mechanisms may leave replacement as the most practical solution.

We recommend diagnosing the complete PSE operating system before replacing expensive exhaust components. There’s no point fitting a new muffler if the real problem is a faulty vacuum solenoid that will still prevent the new one from working. And while we’re all in favor of a Porsche that sounds good, having the sports exhaust permanently stuck in loud mode isn’t necessarily ideal when you’re leaving the house at six in the morning. The neighbors might have a slightly different opinion!

Symptoms : Oil Residue in Coolant Reservoir – Peanut Butter!

Under the worst circumstances, oil in the coolant can look like peanut butter in the coolant reservoir. It typically starts out as an oily film and continues to get worse over time. There are many potential problems associated with this sign – oil could be getting in to the coolant from a blown head gasket, or from a crack in the cylinder head, or a crack in a cylinder liner, or the oil cooler. For sure, coolant in the oil and visa versa is a bad sign and diagnosing the problem often requires multiple steps.

Boxster – Oil in The Coolant – The Easy Approach

The simplest place to start is by replacing the oil cooler – this is the easiest and least expensive item to tick off the list of possible problems. Generally the likely issue is caused by the coolant and oil swapping places through the oil cooler membrane.

Assuming the the oil cooler is the issue, it sits beneath the intake and is exchanging heat between oil and coolant at a barrier level. When the barrier separating the two fluids inside the cooler breaks down, fluid can be exchanged – sometimes in both directions. The result is oil in the coolant and worse, coolant in the oil.  Coolant in the oil is a quick way to needing a new engine!

Replacing The Oil Cooler

If after replacing the cooler, you need to go to the next stage, having a new oil cooler is not the end of the world and at least eliminates the cooler as the source immediately.

If replacing the cooler does not solve the problem, the remaining options are expensive and likely require major engine surgery. This is where a specialized repair shop can help to quickly and cost effectively get to the route cause of the issue.

Symptoms : Low or Flashing Coolant Light

In general, the Porsche Boxster has a reliable cooling system. However, there are several common areas where coolant leaks can develop, particularly as the vehicle ages. Identifying the source of a coolant leak isn’t always straightforward.

Coolant Reservoir Leaks

One of the most frustrating leaks is a small crack in the plastic coolant reservoir, particularly on the earlier 986 and 987 models. This usually shows up as a coolant smell while driving, accompanied by minor coolant loss over time. Eventually, a small crack can expand and suddenly release a significant amount of coolant. Replacing the reservoir is relatively inexpensive, but access can be difficult.

A healthy cooling system should not continually lose coolant. Although minor changes in the reservoir level can occur due to temperature variations, persistent coolant loss, including on later 718 models, should always be investigated. In more serious cases, unexplained coolant loss on older M96 or M97 engines may indicate an internal engine problem, such as a cracked cylinder liner.

Significant coolant loss can quickly cause overheating and potentially catastrophic engine damage.

Leaking Radiators

On the Boxster, the radiators are low down and exposed to incoming road debris. Small holes in the radiator can be difficult to see without removing the front bumper and searching for the telltale white coolant stain. Often the holes are not caused by debris hitting the radiator but are due to deterioration of the seals in the corners of the radiators.

Leaf and road debris is not easily cleaned out from the depths below the bumper and can hold moisture against the radiator causing metal corrosion. We recommend cleaning the radiator areas regularly or adding aftermarket screens to the front of the openings to reduce the problem.

Leaking Hose Connectors

The newer models have the push-click-lock type of hose connector – no clamps. These are easy to get on and off but have a nasty habit of becoming one-time use if not removed carefully. If you have to remove a hose with this type of connector, ensure the connector is correctly seated and the cooling system is pressure-tested to confirm there are no leaks.

718 Water Pump Failure

718 Water Pump Failure
Water pump failures are relatively common on Porsche Boxster engines, including the later 718 models. The underlying mechanical problems are similar across generations, although some proposed solutions have been overhyped.

The bearing supporting the water pump shaft wears over time, allowing the shaft and pulley to develop excessive movement. This can produce a knocking or rattling noise, sometimes accompanied by a coolant leak. As the bearing deteriorates, the shaft can wobble sufficiently to damage the plastic impeller. Broken impeller pieces can circulate through the cooling system, restricting coolant flow and potentially causing overheating. Removing plastic debris from the front radiators can be difficult and time-consuming.

Identifying a Failing Water Pump

The water pump is accessible through the interior engine access panel. One of the simplest ways to identify a failing pump is to observe the pulley with the engine running. A visibly wobbling pulley is a strong indication of a worn water pump bearing and the need for replacement. This is a visual inspection only. Keep hands, clothing and tools clear of moving components. With the engine switched off, the pulley can also be checked for excessive play.

Plastic Versus Metal Water Pump Impellers

A popular recommendation is to replace the original plastic impeller pump with an aftermarket metal impeller version. While metal may initially appear to be a stronger solution, it introduces another potential problem.

If the pump bearing subsequently fails, the metal impeller can contact and damage the surrounding engine housing. In severe cases, this can cause permanent damage and introduce metal debris into the cooling system. By comparison, a failing plastic impeller is less likely to cause this type of damage, although broken plastic pieces can still restrict coolant circulation.

We recommend retaining the original plastic impeller design and using a quality replacement pump.

Preventative Maintenance and Inspection

Some Porsche specialists recommend replacing the water pump preventatively every 40,000 miles or four years. However, this is a preventative workshop recommendation rather than a universal Porsche maintenance requirement.

A better approach is to inspect the water pump regularly, particularly as mileage increases. Check for pulley wobble, bearing play, unusual noises and signs of coolant leakage. A pump displaying any of these symptoms should be replaced before a complete failure causes overheating or damage to the cooling system.

Front Coolant Pipe Leak

The 2.7L and 3.4L Boxster engines feature plastic coolant connections at the front of the engine that can develop leaks as they age. The seals between these components and the engine deteriorate over time, allowing coolant to escape and run down the front of the engine. Porsche has revised some of these components, so we recommend checking for the latest applicable replacement parts.

The water pump is simple to reach from the panel inside the car and checking the amount of play on the pulley is relatively simple. With the engine running, observe the pulley and see if there is any sign of wobbling. If the pulley wobbles replace the water-pump. Most early Boxster owners have already completed this work at least once. Under worst circumstances, you can hear the water pump knocking from inside the car just behind the driver seat. The water pump also has a nasty habit of falling apart, with the vanes being broken off. This can lead to a lack of coolant flow and rising engine temperatures.

A common and frustrating issue with the early Boxster is a small crack in the coolant reservoir. It often starts with a faint coolant smell while driving and slow fluid loss. The reservoir can suddenly split and dump all the coolant risking engine overheating.

Replacement isn’t costly but is tricky due to the tight space. Replacement plastic reservoirs can frustratingly be cheap and not well made, often leading to repeating this job multiple times over the ownership lifecycle. We recommend you get the part from Porsche for the latest and best quality.

Symptoms: Engine Overheats and Loss of Coolant

Each cylinder bore in the engine case half of the Boxster engine is lined with a one-piece sleeve or liner. A crack in the cylinder liner of the engine can show up in a number of ways from overheating, loss of compression to oil consumption. Often, the problem is not simple to diagnose because the cracks can take a long engine running period before they start to work their magic.

987 Boxster Cracked Cylinder Liner

Here’s a first hand example. Customer tows a 987 to us. A coolant hose had exploded – one of the main pipes leading to the front radiators. Customers says the car didn’t over-heat, the hose just exploded. We replaced the hose, refilled the coolant, test drove the car for 30 mins – everything was perfect.

The customer calls the day after picking up the car and driving 1-hour to get home – the car flashes low coolant light and we establish that all the coolant has disappeared from the reservoir.

We scanned the car – no overheating and no faults or events were recorded. We know we filled the coolant to the correct level initially so, we refilled the coolant, ran the engine and drove the car – it’s perfect. Where did that coolant go?

Suspicious of a cracked liner, we decided to let the engine run at idle for a while. The engine ran perfectly at a steady temperature for approx. 55 mins. Then all of a sudden, it rapidly started to get hot, a coolant burning smell appeared in the exhaust and the coolant level started to drop quickly. Once the engine had cooled down, we could repeat this perfectly – approx. 55 mins of running and it would overheat and consume the coolant.

Long story shortened – once we had dissembled the engine, we found a series of micro fractures in the cylinder linings. It took nearly an hour of running for these cracks to open enough for the engine to start consuming the coolant. The engine required a full rebuild and liner replacement to solve the problem.

Symptoms: Warm Air From Air Conditioning System or Loss of Refrigerant Over Time

If your Boxster AC system blows warm air, the most common issue is a lack of refrigerant. Over time the refrigerant from the AC system will find its way out of the hoses and joints. If, however, you refill the system and sometime later the system is again low on refrigerant, there is clearly a larger than normal leak.

Damaged Front Condensers

Leaks can occur at any section joint or hose, however, one of the most common and missed places for the leak is at the lower corner of the front condensers.

Debris from leaves and road dirt can build up tucked in the extreme lower corner of the condensers of the Boxster. The debris can hold moisture and degrade the aluminum to point were a hole can appear. This is almost impossible to see or clean out without the bumper being removed.

The refrigerant leak often goes undetected, even to a sniffer, without the debris being cleaned away. Check this thoroughly before making any other assumptions. The AC compressor for example, rarely has issues and a low refrigerant situation can prevent the compressor from engaging.

Faulty Change Over Valve (COV) Solenoids

The vacuum solenoid or change over valve has been an issue on all the 981 chassis.

The device is designed to direct engine vacuum to effect a mechanical change when requested to by an electrical control unit e.g. open a vent, change the position of an exhaust flap, redirect hot air from feet to screen etc. Likely systems effected include:

1. Air Cleaner Flap
2. Acoustic Simulator
3. Heater Shut-Off Valve
4. Exhaust Flaps
5. Coolant Shut-Off Valve on Engine Bypass Circuit
6. Tuning Flaps
7. Shut-Off Valve on Heat Exchanger for Gear Wheel Set Oil
8. Shut-Off Valve for Clutch Fluid Heat Exchanger (PDK ONLY)
9. Fuel Tank Vent Valve

Porsche has used the COV in many circumstances throughout the 981 chassis, so if you have a failure related to a mechanical device controlled by vacuum, look for a failure in the COV solenoid in the system first.

A common failure on the 718 cars is a left or right side radiator fan running continually at high speed at start up or during short drives even in cold outside temps. This is typically caused by a failed relay.

The cooling fan system is designed to run permanently with the relay activating the stop when the coolant temp does not require the fan to run. With a failed relay the default is for the fan to run continuously for protection against over heating.

Symptoms: Gear Shifter is Floppy or Loose, Inconsistent Gear Changes or Stuck In Gear

Boxster models fitted with a manual transmission can often experience problems with the gear shifter mechanism.

The gear shifter operated by the driver, is connected to the transmission by two cables. Over time these two cables become worn and the result is a sloppy gear change, missed gear or a transmission that refuses to come out of the gear selected.

Checking the Shift Cables For Wear

There’s lots of potential for these two cables to have issues at either end. At the transmission end the cables can break, the small connectors on the end of the cable come off and they can degrade with exposure to the elements. At the shifter end, the cables can become notchy, worn or stretch.

Upgraded Cables and Short Shifter

There is adjustment in the cables, however the original cables in the older cars have been improved and we recommend replacing them. Missing a gear through a worn shifter cable is a recipe for disaster and can lead to serious engine or transmission damage.

Upgraded versions of the cables typically produce a crisper and better feeling gear change. The movement or throw on the Boxster shifter has always been a little long. While cable replacement work is underway, it’s a great time to install a short throw shifter to replace the factory version.

The Tiptronic transmission in the 986 is generally very reliable and relatively straightforward to repair. Fluid maintenance at appropriate time or mileage is critical. Often, maintenance will be neglected because of lower mileage. On a used 986 with Tiptronic, it’s important to understand the maintenance history and catch up if necessary. Known issues are shown below:

Slow or Harsh Shifting

Symptoms: Delayed gear changes, rough shifts, or failure to engage gear.
Causes: Low or old transmission fluid, worn valve body, or aging valve body solenoids.
Repairs: Fluid and filter change. In some instances, valve body rebuild or replacement.

Transmission Overheating

Symptoms: Warning lights, limp mode, or erratic behavior after spirited driving.
Causes: Clogged transmission cooler or radiator, or low fluid level.
Repairs: Replace the transmission cooler and ensure fluid is at the correct level.

Electrical Control Issues – Faults

Symptoms: No response to gear selector, stuck in gear, dash warning lights.
Causes: Faulty Tiptronic control module, shifter switch, or wiring faults.
Repairs: Diagnostic scan to locate faults; replace control module or sensor if necessary.

Torque Converter Problems

Symptoms: Shuddering at low speeds, poor acceleration, high RPMs with low power.
Causes: Worn or failing torque converter lock-up clutch.
Repairs: Torque converter replacement.

Symptoms: Gear Selector Moves With Key Removed, Ignition Key Sticks or Is Difficult to Remove

Some early Porsche Boxster 986 models fitted with the Tiptronic automatic transmission were subject to a safety recall concerning the cable connecting the ignition lock to the transmission gear selector.

The cable is designed to prevent the transmission from being shifted out of Park when the ignition key has been removed. Unfortunately, Porsche discovered that the cable could be incorrectly adjusted during production, allowing the gear selector to move from Park into another position with the key removed. In some cases, the ignition key can also snag or become difficult to remove.

This might sound like a minor inconvenience until you realize the car could roll away if the gear selector is accidentally moved out of Park without the parking brake applied. Not exactly a feature anyone asked for!

Porsche Safety Recall A305 – 1997–2003 Boxster

Porsche issued safety recall A305, also identified as NHTSA Campaign 03V004000, affecting certain Tiptronic-equipped Boxster models manufactured between November 1996 and May 2002.

The recall requires Porsche to inspect and adjust the key-lock cable, regardless of whether the mechanism appears to be functioning correctly. This is an adjustment procedure rather than a recall requiring replacement of the complete transmission or ignition system.

If you own an early Tiptronic Boxster, check the VIN with a Porsche dealer to establish whether the recall applies and whether the repair has already been completed. Don’t assume that because the car is more than 20 years old, the work must have been done.

A sticking ignition key can also result from a worn or failing electrical ignition switch, which is another known problem on the early Boxster. However, the ignition-switch problem and recall A305 are two different issues. Identifying which one is causing the symptoms is important before replacing anything.

Until the problem is resolved, always apply the parking brake when parking the car and have the interlock inspected. We wouldn’t recommend experimenting with moving the gear selector out of Park to see what happens. There’s really no need to find out the hard way!

Symptoms: PDK Failure Light, Rough Gear Changes, Transmission Faults, Emergency Transmission Run Warning on Dash

The Porsche-Doppelkupplungsgetriebe – which translates to Porsche double-clutch transmission or PDK (now that’s when you really need an acronym!) has been the subject of a number of failures. Porsche Boxster owners have experienced failure of the PDK transmission. For more information, see our page dedicated to PDK failures, symptoms, and faults with potential resolutions.

The PDK is essentially an automated manual transmission. It uses two gear sets and two electronically and hydraulically controlled clutches to deliver incredibly fast gear changes. While one gear is engaged, the next can already be selected, allowing the transmission to change gears with almost no interruption in power delivery.

The seven-speed PDK used in the Boxster from the 987.2 generation onwards was developed specifically for Porsche in cooperation with ZF. Although similar dual-clutch technology is used by other Volkswagen Group brands, the Porsche PDK is not simply another VAG transmission with different software. The mechanical design, transmission control and application are specific to Porsche.

The mechanical gear sets have generally proven very robust. Most of the problems we see concern the electronic and hydraulic control systems, internal sensors and clutch operation rather than broken gears. That’s an important distinction when deciding whether the complete transmission really needs replacing.

There are a number of ways in which the PDK in the Boxster can fail. Most show up as a collection of warning lights on the dash and an eventual refusal to do anything. The standard solution is often to replace the complete PDK. This is very expensive and, in many cases, completely unnecessary.

This seems like a good idea until you realize that much of the transmission is perfectly healthy! The problem is often a specific component that can be repaired or replaced. Unfortunately, a lack of understanding, limited parts availability and an unwillingness to dig deep have resulted in many perfectly repairable PDK transmissions being replaced unnecessarily.

Components and Failures

Transmission Control Module – TCM

The connection to the car and communication of instructions to the transmission, come from an external module called a transmission Control Module (TCM). While this rarely has issues, it can become confused and has been the subject of a number of software revisions. Re-flashing the TCM doesn’t usually solve problems, but ensuring you have the latest software revision can’t hurt. This is where diagnostic faults are stored.

Mechatronic Unit – Valve Body

The TCM sends instruction to the Mechatronic unit or valve body inside the transmission. The Mechatronic unit is a complex series of electronics, hydraulic valves and sensors. These devices are managed by a control module attached to the Mechatronic unit. This is the system which enables gear changes and controls the transmission functionality.

Problems with the Mechatronic unit vary, but commonly include failure to select gears, rough gear changes, etc. The physical components of the transmission are robust, so this unit is often the most economical place to start for most issues.

Internal Sensors

Connected to the Mechatronic unit are a number of sensors throughout the transmission. These determine the operating conditions within the transmission. For example, the temperature of the fluid, the rotational output speed, hydraulic clutch pressure and movement of gear selectors. Failure of these sensors is very common. Early on, Porsche routinely replaced the wiring and trans temp sensor in most of the PDKs.

However, the problem did not go away and has re-occurred on the same transmissions further down the road. The temp sensor problem can show up on almost any model with a PDK. See our PDK problems page for more detail on the sensor problems.

Clutch Pack

The clutch pack has proven to be very robust and generally does not fail with normal use. Over extended mileage this will become a wear component that will need to be replaced. The failures of the clutch that have occurred, are usually on performance enhanced engines delivering too much torque for the clutch plates. At higher torques, the clutches slip resulting in highly accelerated wear and early failure.

The PDK transmissions in the later cars are very complex and the technology involved is a closely guarded secret. Technicians at Porsche are not required to dissect the transmission and make repairs. They will replace the Mechatronic unit, but often they just replace the transmission as a whole.

We recommend you get a second opinion from a Porsche specialist before you go ahead and replace a PDK transmission. Even leaks, sensor failures and clutch pack issues with the PDK can be resolved without replacing the transmission completely.

Don’t Replace Your Porsche PDK Transmission – It Can Easily and Economically Be Repaired

Expert Porsche PDK Transmission Repair Service

The good news is the Porsche PDK transmission is fully repairable for a fraction of the cost of replacement. And in more good news, repairs of the PDK transmission have led to expert knowledge to be able to recommend additional preventative maintenance that can help avoid the common issues that arise with the PDK.

Recommended Porsche PDK Repair Specialist

We have partnered with MC Squared Autosport and highly recommend their Porsche PDK transmission repair service.

Symptoms: PDK Transmission Warning, Gear Selection Problems, Permanent Fault Codes P1775, P071400 or P184900

Porsche has introduced an important warranty extension for certain PDK transmission control-unit failures affecting the 981 and 718 Boxster models. Under Porsche Technical Information 18/26, eligible vehicles now have warranty coverage for a specific transmission electronics defect for 20 years from the original vehicle delivery date, with no mileage limitation.

The problem concerns a software error within the PDK transmission electronics control unit. Under certain conditions, the control unit stores permanent fault codes that cannot be cleared using the normal diagnostic procedure.

Porsche identifies three specific fault codes:

• P1775 – Protective measures cannot be performed.
• P071400 – Transmission oil sump temperature sensor, open circuit.
• P184900 – Replacement measures active.

The important detail is that these codes relate to a specific software problem. Porsche Technical Information 09/26 explains that an internal software test prevents the permanent fault memory from being cleared. Porsche’s recommended solution is to reprogram the transmission control unit using the appropriate Porsche diagnostic equipment.

This is where things get interesting. Porsche specifically states that replacing components will not resolve this particular fault. So, if somebody recommends replacing your entire PDK transmission because one of these permanent codes is present, it might be worth mentioning that Porsche has a different idea!

Does Your Boxster Qualify for the Extended Warranty?

The warranty extension applies to selected 981 and 982 Boxster models within Porsche’s affected vehicle population, covering eligible vehicles in the USA, Canada and Puerto Rico. However, don’t assume every Boxster with a PDK warning automatically qualifies. Coverage is limited to the specified programming defect and requires confirmation of the VIN and diagnosed fault condition.

The warranty is transferable to subsequent owners, so it may also benefit owners who purchased their Boxster used. We recommend asking an authorized Porsche Center to check the vehicle’s warranty coverage through Porsche’s Central Service System before approving any expensive PDK repair.

Don’t Confuse This With Other PDK Failures

This warranty extension does not cover every PDK transmission problem. Failed internal sensors, hydraulic faults, clutch problems, oil leaks and mechanical damage are separate issues requiring their own diagnosis and repair.

The good news is that many of these problems can also be repaired without replacing the complete transmission. See our guide to Porsche PDK transmission repairs for more information.

The bottom line? If your Boxster develops a PDK warning, get the fault codes properly diagnosed and check the warranty coverage before spending money. Replacing an entire transmission because of a misdiagnosed software fault could be really painful.

Symptom: Clutch Pedal Stuck Down and Leaking Fluid

The early Boxster featured a plastic clutch slave cylinder that was subsequently update to a metal version after initial failures. The original clutch slave cylinder can easily fail leaving a fluid mess and a stuck pedal.

Bleeding the Clutch Slave Maintenance

The clutch slave cylinder should be flushed in the same way that a brake fluid flush is performed on the Boxster. The flush of the slave cylinder should be completed at the same time as a brake fluid flush. Build up of debris and old fluid in the clutch slave cylinder causes inefficient operation of the clutch and can lead to difficult gear changes and wear of the clutch plate.

Here’s What to do When You See PSM Failure on Your Porsche Dashboard

PSM failure can be a common issue on the Boxster, however, because the system is so interconnected, the message PSM failure can be deceptive. The PSM per se has not itself failed. The likelihood is a single sensor or component connected to the system is broken. The interconnection of the systems can result in the reporting of multiple faults and cause significant confusion to the untrained. Commonly a single sensor failure will report multiple faults in various systems. Proper diagnosis of the root cause will save you money versus part replacement guess work.

We highly recommend you seek the professional guidance of a Porsche specialist to diagnose and make repairs to solve the PSM failure message.

If you see PSM messages that also include ABS see our page on brake system messages.

This warning light is associated with a failure in the ABS system on older cars and is shown as a message in the later cars. A minor fault in the system can cause this light to be illuminated.

Here’s what to do – Do not ignore this light. This is a critical safety system and is designed to help you in an emergency situation. Have the car scanned by a Porsche specialist to determine the exact cause of the warning light.

In many cases this can be as simple as a wheel speed sensor.

Symptoms: Brake Booster Warning, Power Brake Error, Hard Brake Pedal, Check Engine Light, Fault Code P055600

The Porsche Boxster uses a vacuum-assisted braking system to reduce the effort needed to operate the brakes. Unfortunately, problems with the brake booster vacuum supply, pressure sensors, electrical connections or vacuum pump can trigger warning messages and potentially reduce braking assistance.

These problems can occur on different Boxster generations, although the design of the vacuum system and the components involved vary by engine and model year. One of the more common diagnostic faults is P055600, which indicates that the brake booster vacuum pressure reading or system performance is outside the expected range.

The warning may appear when starting the engine, sometimes accompanied by a check engine light. In more serious cases, the brake pedal can become unusually hard, requiring considerably more effort to stop the car.

Diagnosing Brake Booster Problems

A brake booster warning doesn’t automatically mean the booster itself has failed. Vacuum leaks, damaged hoses, faulty check valves, pressure sensors and electric vacuum pump problems can all produce similar symptoms.

Start by checking the vacuum supply and identifying any leaks or damaged connections. The pressure sensor readings and operation of the vacuum pump should also be checked using Porsche-compatible diagnostic equipment.

Replacing the brake booster seems like a good idea until you realize the problem is a split vacuum hose or a faulty sensor! There’s no point replacing expensive components until you’ve established what’s actually wrong.

Porsche 718 GTS 4.0 – Brake Booster Software Update

Porsche has identified a specific brake booster warning affecting certain 2021–2024 Boxster GTS 4.0 models. The warning typically appears when the engine is started after the car has been sitting for more than 25 minutes. The engine management system checks how quickly the electric vacuum pump develops vacuum and records fault P055600 if the pressure difference doesn’t meet the expected value.

Porsche found that the problem is more likely to occur at higher altitudes, where lower atmospheric pressure affects the diagnostic test. In April 2026, Porsche revised Technical Bulletin 2309.3 to include an updated diagnostic procedure and a software solution.

The workshop must first inspect the vacuum connections, pressure accumulators, electric vacuum pump and pressure sensor for actual faults or leaks. If the mechanical system checks out, Porsche specifies a DME software update using PIWIS diagnostic software version 42.900.010 or newer.

This is where things get interesting. The car can report a brake booster fault when the real problem is the way the engine management system interprets the vacuum readings. Replacing expensive brake components to fix a misdiagnosed software issue is expensive.

The software update is specific to the vehicles and conditions identified in Porsche’s bulletin. It is not a universal solution for every Boxster brake booster warning.

Can You Continue Driving?

A brake booster warning should never be ignored – the message usually suggests driving is ok. If vacuum assistance is genuinely lost, the brakes may still operate, but considerably more pedal effort will be required to stop the car. If the pedal becomes unusually hard or braking performance changes, stop driving safely and arrange professional inspection rather than continuing to drive.

We recommend having an experienced Porsche specialist check the recorded fault codes, vacuum system and applicable Porsche technical information before replacing any components.

The bottom line? A brake booster warning doesn’t necessarily mean a failed brake booster. Diagnose the problem first, replace parts second.

This message relates to the ability for the electrical system to operate the parking brake. The parking brake is applied via electric motors.

Here’s what to do – Hopefully at this stage the parking brake is off. Do not attempt to operate it. If the parking brake is stuck on, then a painfully expensive tow charge will likely apply!

Head to a Porsche specialist and scan the car to identify the failed component. In this case, the component is typically a position sensor.

The PASM or Chassis warning messages on the later Boxster models are never very specific. Problems in the system vary from a simple sensor or wiring fault through to a failed electronic shock absorber or PASM control unit.

PASM electronically adjusts the suspension damping based on driving conditions. It doesn’t level the car, but it does rely on information from several other vehicle systems. Consequently, a failure in one component can produce multiple fault codes and warning messages that don’t necessarily identify the actual problem.

This is where diagnosis becomes important. A PASM warning doesn’t automatically mean you need new shock absorbers. We’ve seen plenty of expensive components replaced unnecessarily because someone assumed the fault message identified the failed part. A little investigation can save a considerable amount of money.

We recommend scanning the PASM system with Porsche-compatible diagnostic equipment and checking the sensors, wiring and electrical connections before replacing expensive suspension components. If the problem isn’t obvious, seek the help of an experienced Porsche specialist rather than playing parts roulette.

Later Boxster models feature electronically assisted power steering. Fault messages associated with the power steering typically indicate a loss of steering assistance or support and suggest you can drive on. This means the steering will feel heavy and requires more effort. This can be a potentially dangerous situation and should be diagnosed as quickly as possible.

Failure of the electronic steering rack is not that common. These faults are normally caused by power supply failure through a faulty relay.

Often a knocking or low thud can be heard from the front suspension on an older Boxster and commonly on the rear of the 981. This is often caused by the drying or failure of the upper shock or strut mount. Above the front and rear suspension strut is a plate with a rubber bushing. The rubber commonly drys and declines over time. This allows the strut to move and hit the body as it rides over bumps producing a low frequency thump.

Porsche PADM is active drivetrain mounts. Essentially, these are electronically controlled engine mounts designed to stiffen side to side and when launching the car. These electronically controlled engine mounts also control the engine movement when cornering and are designed to improve performance, comfort, and stability.

The engine mounts commonly fail and many have been replaced before an updated version was available. Worth checking the wiring and the connector before assuming the engine mount has failed.

Boxster Suspension Issues

The Boxster suspension is extremely durable. However, rubber bushings, control arms, and struts can be worn with age. The most common issues are as follows:

Worn Control Arm Bushings

• Symptoms: Clunking noise over bumps, uneven tire wear, loose steering feel.
• Cause: Original rubber bushings degrade over time.
• Fix: Replace control arms or bushings. Many owners upgrade to polyurethane or monoball bushings for improved precision.

Failed Lower Control Arms

• Symptoms: Clunking, instability under braking, poor alignment retention.
• Fix: Replace with OEM or upgraded units

Top Mounts / Strut Mounts

• Symptoms: Squeaking, clunking over bumps, poor ride quality.
• Fix: Replace top mounts when changing struts/shocks. Consider upgraded mounts or aftermarket alternatives for improved feel.

Worn or Leaking Shocks or Struts

• Symptoms: Bouncy ride, nose dive when braking, poor cornering stability.
• Fix: Replace shocks. Many aftermarket options available.

Sway Bar End Links & Bushings

• Symptoms: Clunks or rattles during cornering.
• Fix: Replace worn end links or sway bar bushings. Consider adjustable end links if running coilovers or lowered ride height.

Alignment & Ride Height Issues

• Symptoms: Pulling to one side, excessive inner tire wear.
• Fix: Get a professional alignment, ideally from a Porsche specialist. Many Boxster models are misaligned due to aged components.

Symptoms : No Crank or Slow Crank

Porsche Boxsters are often garage queens and not driven as much as many other cars – rarely are they daily drivers. During any down period the car will continue to use some battery power – in Porsche’s case, usually more than would be expected from similar vehicles. This can very quickly lead to a flat battery.

Losing battery power resets a number of important systems and can cause unnecessary headaches with everything from emissions to electronics and comfort items such as cabrio roofs. We recommend you use a battery maintainer any time you store or do not drive the car for an extended period – 2 weeks or more. Leaving the battery to drain completely usually shortens the life of the battery as well.

How To Access The Battery With No Power

A flat battery on a Boxster can be a pain. To access the battery or engine compartment requires battery power for the electric hood release – not easy with a flat battery. If this happens, use the following procedure:

• Open the left door
• Connect an external battery power source to fuse C3 in the interior fuse panel
• With the door open, flip the door latch mechanism to the closed position
• Use the key to lock and unlock the door
• The front hood release should now function

Symptoms: Key Stuck in Ignition or No Start

This is a common failure on the Boxster.  Turning the key will not start the car or the key has become stuck in the ignition switch.

This problem is typically caused by a failure in the ignition switch mechanism. Replacing the electrical portion of the switch is fairly straight forward and typically solves the no start problem immediately.

However, on some occasions it may be necessary to replace the mechanical portion of the switch as well. This is a little more involved and requires some additional skills. We’d recommend a repair shop tackle this problem for you.

Key Failure

The ignition key communicates with the car during the starting procedure. The key includes a small electronic transmitting device that is matched to the car and a small battery to power it. If the key fails to open or lock the doors and will not start the car, replace the battery in the key first, paying particular attention to the orientation of the original battery.

On some occasion it may be necessary to replace the internal electronics of the key or the whole key itself. This can be done by some third party repair shops with the right access to Porsche systems, however, because this is a security device it may be necessary to visit your local dealer.

Symptoms: Windows Do Not Drop On Door or Top Opening

If your Porsche Boxster battery has gone flat or required a change, you may experience this issue. This issue, if related to battery power, can be generally solved through performing a vehicle handover using the diagnostic device.

However, if the condition is not related to battery failure, then it is likely there are a number of other scenarios that can cause the window to misbehave:

1. Window does not drop when opening the door from the inside: This is usually caused by the inner door handle micro switch malfunctioning.
2. Window does not drop when opening the door from the outside: This is usually caused by the outer door handle micro switch malfunctioning.
3. With the door open, the window goes back up when you release the door handle, making it very difficult to close the door with the glass all the way up. Alternatively, the window does not drop when using either the inside or outside door handle: This is usually caused by the door latch mechanism micro switch.
4. When operating the convertible top, neither windows drop: This is usually caused by the convertible top latch micro switch.
5. If a window does not drop enough and you can push down the window the extra travel before stopping, the typical cause is the window regulator.

Go through the functionality of the door and window in question from locking to unlocking to open close from both inside and out. Commonly, this will narrow down the problem to a micro switch in one of the above mentioned areas.

Symptoms: Random Interior Faults – Windows, Seats, Air Bag etc.

This problem is most prevalent in Boxster models because of the cabrio roof.

On occasion, the Boxster will exhibit strange and seemingly random electrical misbehavior of interior systems. This could be interior lights staying on, air bag faults, seat malfunctions, etc. Often this can be traced back to a single control module. Porsche placed the module that controls interior settings under the drivers seat.

Due to the location and proximity to the driver door and window, this module can sometimes become water damaged – especially on cabriolet models like the Boxster. Once the module has got wet, it will often take time to slowly corrode and produce strange electrical faults or misbehavior.

If you left the top down in a rain shower, had the driver window open when it was raining, your top leaks, or live in a climate where significant rain could enter when the driver door is open, you’re a good candidate to have this problem.

Symptoms: Top Won’t Move, Opens Unevenly, Gets Stuck or Won’t Close

The Boxster convertible roof is generally reliable, but as these cars age, problems with the opening and closing mechanism are not unusual. These range from a deteriorating rear window to the roof becoming stuck or opening and closing unevenly.

On the early 986 Boxster, the plastic rear window can become cloudy, brittle or cracked. This is relatively easy to solve. A good automotive upholstery or convertible top specialist can replace the old, tired plastic window without necessarily replacing the entire roof. Some shops even offer a glass rear window upgrade. The later Boxster models have glass rear windows, so this problem is largely confined to the early cars.

Other issues with the roof concern the opening and closing mechanism. Porsche revised the motors and drive components on the older Boxster to cure some common problems. Unfortunately, some of the updated parts are not compatible with the originals. This can turn what initially looks like a simple repair into something considerably more expensive. Before replacing the entire drive system, make sure the individual components have been checked and the necessary parts identified.

Another common problem is the failure of the bushings or joints in the roof support arms. This causes the familiar lopsided effect, where one side of the roof moves further than the other. The good news is that replacing the affected support arm or linkage is generally a relatively inexpensive repair compared with replacing the complete mechanism.

Diagnosing Convertible Roof Problems

While the roof mechanism involves numerous components and can look complicated, the actual opening and closing process is relatively simple. There is a sequence of events that must occur between pressing the button and the roof completing its movement.

If one step doesn’t happen, the roof stops working correctly. Start by identifying exactly where the sequence fails. Check the roof latch, microswitches, drive cables, linkages and motors before assuming the complete roof mechanism has failed.

This seems like a good opportunity to replace the roof motor until you realize the problem is a faulty microswitch! A little diagnosis can save a considerable amount of money.

Convertible Roof Drainage and Water Leaks
Another issue, particularly on the older 986 and 987 models, is blocked roof drainage channels. Leaves and debris collect around the roof drains and prevent rainwater from escaping. The water can then find its way into the passenger compartment, soaking the carpets and potentially damaging electrical control modules.

This can become a very expensive problem for something that started with a few leaves! We recommend checking and cleaning the roof drains regularly, particularly if the car is parked outside.

Storing Your Boxster

One final note on storage. Don’t store the car with the roof down for extended periods. The fabric can shrink or develop stubborn creases, making it difficult to stretch back into the closed position. Always store the Boxster with the roof up.

Symptoms: Wet Carpets, Damp Interior, Musty Smell, Random Electrical Faults, Alarm or Central Locking Problems

The Porsche Boxster has drainage channels around the convertible roof designed to carry rainwater away from the passenger compartment. Unfortunately, these drains can become blocked with leaves, dirt and other debris, particularly on cars parked outside.

This is a common problem on the older 986 and 987 models, although later Boxsters can also experience drainage problems.

When the drains become blocked, water collects around the roof mechanism and eventually finds its way into the passenger compartment. Often the first sign is a damp carpet behind or underneath the seats. However, the carpet can feel perfectly dry on top while the thick foam underneath is soaking wet.

And here’s where things get expensive!

On the earlier Boxster models, Porsche located sensitive electrical control modules beneath the seats. Water entering this area can damage the immobilizer, alarm and central locking electronics. The result can be a collection of seemingly unrelated electrical problems, including windows that misbehave, doors that won’t lock, alarm problems or a car that refuses to start.

It’s tempting to start replacing electrical components when all these faults appear. This seems like a good idea until you realize the real problem started with a few leaves blocking a drain!

Finding and Preventing Roof Drain Problems

Check the drainage channels around the convertible roof regularly, especially after heavy rain or when the car has been parked beneath trees. Carefully remove any accumulated debris and confirm that water can drain freely through the intended outlets.

Don’t attack a blocked drain with high-pressure compressed air or a piece of stiff wire. It’s possible to damage or disconnect the drain tubing and turn a small blockage into a much bigger water leak.

If you discover wet carpets, don’t simply dry the visible surface and assume everything is fine. Check the padding underneath and inspect the electrical components for signs of moisture or corrosion. The damage can develop slowly, long after the original water leak.

We recommend including roof drain cleaning in the annual maintenance inspection. It’s a simple preventative task that can save a considerable amount of money.

After all, replacing an immobilizer because nobody cleared a few leaves out of the roof drains seems a little excessive to us!

Symptoms: Lift The Lid and It Falls Down On Your Head!

This is very common and very annoying for the person with their head stuck in the trunk looking for something.

The hydraulic struts on either side of the hood or lid fail over time. This is annoying but also dangerous – the latch on the hood can give your head a nasty blow if it falls down unannounced.

Replacing the struts is simple and they are available online at low cost. You’ll have a much better relationship with a repair shop that works on your car if you fix these, not to mention the cost of the lid falling on the wife!

Many 981 customers have encountered a rattle or squeak noise that seems to be coming from the steering column, instrument cluster or forward console area. Porsche issued a TSB for its workshops that identifies a potential issue related to the fuel tank.

There are foam insulating pads that sit between the fuel tank and the bodywork that allow some movement of the fuel tank but cushion the sound of the tank hitting the body. Over time, these pads have either worn out or moved due to a lack of adhesive. The result is a strange rattle or squeak noise from the front of the 981 that appears at first to be coming from the dashboard.

Revised foam pads are available to solve this problem. In some cases, replacement of the pads can be achieved without removing the fuel tank. However, for many removal of the fuel tank and replacement of the pads is necessary.

The rear spoiler on the Boxster is automatically deployed based on speed but can also be manually controlled through an interior switch.

Deployment Speed

• Automatically rises at approx. 75 mph (120 km/h).
• Automatically retracts at approx. 50 mph (80 km/h).

Common issues with the rear spoiler include being stuck up or down and a general failure to deploy. If there’s a malfunction, a spoiler control failure message or warning light may appear on the dashboard. Spoiler failure issues can be expensive as component parts for the spoiler are not always available individually. Thoroughly check the electrical supply and wiring to the spoiler – these are common failure areas.

Symptoms: Unusual Electrical Behavior

In some regions, such as the Midwest or Northeast, cars are often stored over the winter months and not driven much until all that nasty white snow stuff disappears. However, the fact that you have your car tucked away in a warm, clean and perfect garage does not mean that its is alone!

Our small rodent friends that we share this planet with, are seeking out the exact environment you have created for your Boxster storage. Small rodents are experts at finding a safe place and hiding beyond your view.

What Looks Good To A Rodent?

The cabin air filter makes the perfect place for a warm nest – when was the last time you looked in there? Also, the center of the engine, right below the intake, is a perfect place for the safe consumption of food. It’s supplemented by wires that are coated with a plastic made from corn and on cold, long dark winter nights when food is in short supply, that wire seems pretty tasty. Of course, you are blissfully unaware of all of this until the car displays strange engine faults and a musky odor from the air vents!

On one occasion, we removed a whole mouse family from a Boxster that had eaten the wiring harness, destroyed the carpets, (top stored down) and had eaten most of the cabriolet top.

Take rodent precautions even if you are certain you don’t have that problem.