Cayman 718 GPF Failure

[JohnCRS]

You are correct on many fronts Ian, as we have known for a long time that Porsche can simply stonewall us and deal with issues (or not) on a case by case basis. In a nutshell, if they demand £9k to turn the CEL warning off and, if you don't want to pay, then please take you car away, there is not much we can do about it, however outrageous that may be. Dave has saved many members a lot of money helping them deal with this demand, but now Porsche and their OPC's do seem to be digging in.

We can of course keep fighting individual battles and will wherever possible. But probably our best opportunity for progress is to research ways of bypassing the CEL ash measurement warning. After all we know it is false and the GPF is not blocked.

 

[Voodoo_Blue]

There will of course be a point where some owners of cars likely to be affected by this issue will abandon OPCs in favour of independents for servicing and maintenance if that's not already happened.

As I understand it many independents have access to PIWIS and may have the ability to reset the CEL when this fault appears without the expense of replacing the filters. I know a number of owners who have a Porsche Extended Warranty use an OPC for servicing but everything else, for example brakes, is done by an independent using Porsche parts so perhaps, as suggested above this is another area where an independent could be more helpful. I wonder if we are able to check this if not already done?

As a club with our direct relationship I hoped we could have done more to champion this issue but it seems that even that unique position is not enough to help the right people see sense. I fear that in the end owners will suffer without the intervention of people like Dave and John unless someone chooses to litigate with all the time and expense that will involve including the loss of good faith.

It seems in recent years Porsche have become more and more intransigent towards their customers and have forgotten that loyalty works both ways. Not a good position to take in their current financial predicament and I suspect will at some point come back and bite them if that's not already happening.

Having said all that I applaud all your efforts to date and wish you a Very Merry Christmas and a Happy New Year.

 

[Voodoo_Blue]

And I thought you might find this interesting.

Porsche Found a Smarter Way to Keep Catalytic Converters Alive — Autoblog

New patent suggests Porsche is looking at repurposing exhaust recirculation systems to clean catalytic converters more efficiently.

apple.news

 

[Cyclemotor1958]

Hi Voodo_ Blue

Without prejudice

Thanks for your kind words, its been quite a journey trying to get us to this point in time.

We can now prove that this emission control fault was present way back in 2019, and its back again, even after these new modified filters have been fitted and re tested.

The Dealers are now aware that we are aware that they cannot expect us to believe that these modified GPF filters are the cause of this fault.

Currently 13 of our owners can verify this, they have lived through the misdiagnosis of this fault. Starting with the appalling treatment by the Dealers, the initial quote, the reason for the fault being down to them not driving the car correctly, or the wrong engine oil being previously used.

Never mind, all the phone calls to the Dealers trying to get some sense of what was going on.

All the time wasted when their cars were at the Dealership waiting for authorisation from Porsche Technical and the Warranty Departments.

And lets look at all the parts that have been fitted to their cars to try and fix this fault, multiple GPF filters, oil air separators, DME control units, differential pressure sensors, turbos, two engine removals, with complete strip downs looking for internal oil consumption evidence.

Nothing reported on both vehicles.

And unbelievably a new engine was fitted which made no difference to the oil ash % that came back, that had been there after the first GPF had been fitted.

So the Dealer had to buy back this car, because between Porsche and them, they couldn't fix it.

To quote 9K now to fit a GPF filter that will certainly not fix this fault, would certainly be misleading our owners with an inaccurate diagnosis of this fault, which has sadly continued for far to long.

The internal memo that Porsche sent to their Dealers in March this year, confirms what we have been saying for the last 2.5 years, they definitely new about this issue, or at least Porsche Technical did.

Don't forget Porsche will have figures of all the GPF filters that have been replaced during the warranty period and after.

You would have thought that when they realised they had an issue with these filters, and they had to modify them, why didn't they replace them all in the beginning, a possible recall.

It makes you wonder if they did know that the modified GPF filters didn't fix this issue, and going forward it would be dealt with by a case by case basis.

Alot easier to do do when the cars out of manufacturing warranty, and the extended warranty doesn't cover it either.

Remember the memo says all vehicles with a production date later than December 2019 should already have the modified filter fitted.

All our cars had registration dates before December 2019

How many of these cars have been sold because the owners were given a 9K quote to replace the filter, and no real credible explanation of how this fault as occurred.

UNANSWERED QUESTIONS.

WHY IS THE SOOT WARNING LIGHT NOT COMING ON, WHEN THE FILTER IS 100% BLOCKED WITH ASH.

WHY IS THERE NEVER ANY SOOT PRESENT WHEN THE FILTER IS SUPPOSEDLY BLOCKED WITH ASH AT 100%

WHY WILL OUR DEALERS NOT DO A BACK PRESSURE CHECK, WE REQUESTED THIS TO BE CARRIED OUT ON ALL OUR CARS, IT WAS NEVER DONE. THEY REFUSED TO DO IT, EVEN WHEN WE SAID WE WOULD PAY FOR THE TEST.

WHY HAVE ALL THESE NEW PARTS BEEN FITTED TO OUR CARS, AFTERALL THE CHECKS LOOKING FOR CAUSES OF HIGH ASH LOADS WERE DETAILED IN THE INTERNAL MEMO.

THE DIFFERENTIAL PRESSURE SENSOR FUNCTION WAS MENTIONED YET THE LOW PRESSURES RECORDED ON ALL OUR CARS WAS CLEARLY IGNORED.

THE OIL AIR SEPERATORS VACUUM CAN BE CHECKED WITH A MANOMETER CONNECTED TO THE OIL FILLER CAP THEY RUN BETWEEN 30 TO 35 INCHS OF WATER AT IDLE WARM ENGINE.

A FAILED AOS WOULD BE OVER 50 INCHES OF WATER, AND PROBABLY HAVE AN ERROR MESSAGE ON THE TESTER OUT OF TESTING RANGE.

NOT TO MENTION THE WHITE SMOKE ON START UP.

THEY ALSO MENTIONED THE TURBO ACTUATOR, WHICH AS BEEN AN ISSUE FOR SOME TIME, THE PIN CONNECTING THE ACTUATOR TO THE TURBO LEVER SEIZES UP, IT JUST NEEDS SOME CLEARANCE, BUT IT WOULD LEAVE, UNDER AND OVER BOOST DTC CODES.

IF YOU THINK ABOUT IT, THIS MEMO WAS WRITTEN TO HELP THE DEALERS DETERMINE THAT NO ENGINE OIL WAS GETTING INTO THE EXHAUST CAUSING EXCESSIVE SOOT REGENERATIONS WHICH WOULD, OVER ALOT OF TIME CAUSE A PREMATURE ASH BUILD UP IN THE GPF.

AND ANOTHER AMAZING THING IS, WE HAVE NEVER SEEN ANY SOOT REGENERATION CODES RECORDED IN ANY OF OUR CARS ENGINE MANAGEMENT SYSTEMS.

THE MEMO ALSO EXPLAINS THAT IF A REGENERATION WILL NOT RESET THE OIL ASH % THEN A MODIFIED GPF FILTER WIll NEEDED TO BE FITTED.

HOW CAN FITTING AN EXHAUST EMISSION PART THATS NOT FAULTY RE SET THE OIL ASH % IN THE SOFTWARE, THIS AS BEEN PROVED THE CASE ON ALL OUR 13 CARS.

We have spoken to two vehicle emission control authorities so far, and we have a few more to contact in the new year, hopefully they will help us get the answers to our questions.

Thanks to all of you that are following this forum, we have 121K views on this issue todate.

Hopefully we will get some good news in 2026.

Have a Merry Christmas and a Happy New Year


Dave

 

[AndyT718]

Recently bought a 2022 plate 2.0 and this thread is rather alarming.

A few weeks back Dave said he had been speaking with a dealer who was able to get the ash load back down to 0%, but only after 4/5 regen attempts and extensive road driving.

From reading the various bits posted here, my understanding is that the ash load is calculated following a regen cycle to burn off the soot within the GPF. This is done via a calculation based on the reduction in differential pressure reading following the regen cycle.

Regen cycles should usually happen during normal driving unless the car is never driven hard enough for sustained periods to get the cat/gpf into the temperature range for a regen to occur. This in turn would trigger the elusive dashboard light.

Suppose the ECU believes it is performing successful GPF regen cycles, but in reality the regens are unsuccessful due to the GPF never getting hot enough to burn off all of the soot build up. This would therefore cause the ECU to believe the ash level to be higher than they actually are and could easily lead to a 100% full code being thrown.

Repeated forced regens and road testing as performed by the dealer in this instance would likely have got the GPF into the required range to start burning off the soot correctly and causing the reported ash levels to drop back down to 0%.

So could the issue here be unsuccessful regens due to insufficient heat causing false ash readings? Was the redesign intended to create more heat in the GPF during the regen process?

 

[911hillclimber]

That's an interesting view, and could be very creditable.
Could well explain the mechanical change to the filter itself rather than software as a solution.

But it has not worked!
Surely Porsche would have not released the change unless proven to resolve the issue, no point in doing that.

 

[Cyclemotor1958]

Hi AndyT718

Without prejudice

Interesting points regarding the heat in the exhaust, our cars unfortunately do not have an exhaust temperature sensor in the GPF filter, unlike the 4.0 cars that have a sensor in both GPF filters.

And they do not appear to have this Ash % issue, that our cars have been struggling with since 2019.

Bearing in mind you need correct exhaust temperature readings to facilitate a regeneration cycle.

Our cars rely on a calculated temperature created by the algorithm, the Catalytic Convertor temperature is also calculated.

Normally if a soot regeneration is required, and it cannot be completed, the driver will be informed by a dashboard message, sadly that system also doesn't appear to work correctly.

This soot driver regeneration system was designed to leave a specific DTC code P2463 , (Particulate filter soot load high).

If this soot regeneration wasn't completed correctly, it puts in another code, 26740

See below three photos supporting the information above.

This would certainly require a workshop regeneration using PWIS, the same that happens on diesel cars, if you ignore the soot warning message.

Yet according to our Dealers and Porsche Technical, our cars have a GPF filter thats blocked up with ASH at 100% and needs replacing.

In our industry its very well known that if your GPF, or DPF is blocked with ASH, you shouldn't even try to carry out a soot regeneration because this can cause other serious issues to your car.

Attempting to force a regeneration on a filter blocked with high levels of ash can cause excessively high back pressure, potentially leading to serious engine and turbocharger damage.

Funny that our cars have no significant back pressure recorded by the differential pressure sensor, and no significant soot values either.

So our Dealers can carry out a soot regeneration with no soot present, and no back pressure in the GPF, to try and re set an Ash-Blocked GPF filter.

The memo that came out in March of this year confirms this is their way of re setting the ASH %.

If it doesn't re set, fit a new modified filter, that was designed to fix this issue again confirmed in the memo.

Unfortunately has we know, these modified filters didn't fix this issue way back in 2019, and certainly don't fix them now. Because a possible fault in the software was over looked.

The fact that we have never seen on our faulty cars the soot driver regeneration message, makes you wonder if this was the issue from day one.

If we removed this function on our diesel cars over night, to inform the driver that a soot regeneration was required, the whole country would come to a grinding halt.

Yet on our cars this situation is ok, according to Porsche Technical who will not answer the most important question we have been asking for the last 2.5 years, why doesn't it work like it should do.

In the handbook it explains what to do if the soot warning comes on, and how to drive the car with lots of deacceleration etc.

You would think that the most important function of an emission controlled vehicle is to monitor and react to soot loadings, and eventually the ASH levels within the filter correctly.

Not in our case.

Hopefully Porsche will do the right thing and get our soot warning lights working, and sort out this ASH issue thats definitely not real.

Dave

 

[Cyclemotor1958]

Hi Guys & Girls

Without prejudice

Hope you all had a great Christmas and a Happy New Year

We have had some more feedback from several Dealers on vehicles that have had new modified filters fitted, and the oil ash % as come back.

They are now saying that the rising and falling ASH load percentages is normal behaviour for this system and the fluctuating oil ash values do not necessarily indicate a fault or malfunction.

So I had another look at the algorithm on the Porsche Patent publication, on page 4 it mentions a static offset of the differential pressure sensor.

This is what we found on Google.

A static offset in a differential pressure sensor reading is used for two primary reasons: calibration and compensation.

1. Calibration and Zero Adjustment
Sensors naturally exhibit a small output error, or "zero drift," even when the actual differential pressure across them is zero (e.g., when the system is off or pressures are equal on both sides).
Correction: Applying a static offset value during a calibration procedure adjusts the sensor's baseline reading to match the true zero point, ensuring that all subsequent measurements are relative to an accurate starting point. This is often referred to as a "zero adjustment" or "position adjust" and is a standard practice to maintain measurement accuracy over time and use.

2. Compensation for Environmental and System Effects
A static offset reading can also be used to counteract external factors that would otherwise compromise the measurement accuracy:
Static Line Pressure: In differential pressure (DP) applications, a high background "static line pressure" can physically deform the sensor's diaphragm, introducing errors into the differential reading. By applying a known offset value (often determined during manufacturing or field calibration), the control system can correct for this effect, ensuring the reading accurately reflects only the difference in pressure, independent of the absolute line pressure.

A STATIC OFFSET in a differential pressure sensor reading can cause significant issues with ash loading estimation and management, primarily leading to inaccurate readings, suboptimal regeneration, and potential damage to the system.

Key issues include:
Inaccurate Ash Loading Estimation: The offset means the control system is working with incorrect pressure values, leading to miscalculations of the actual amount of ash in the filter [1].

Premature or Delayed Regeneration:
A positive offset (reading higher than actual pressure) would indicate the filter is full sooner than it actually is, triggering premature regeneration cycles [1]. This wastes fuel and can reduce the lifespan of the regeneration system components.
A negative offset (reading lower than actual pressure) would delay regeneration until the filter is dangerously full, potentially causing excessive backpressure that could damage the filter or the engine [1].
Increased Fuel Consumption: Inefficient regeneration cycles directly impact vehicle or system efficiency, increasing fuel usage and operating costs [1].
Component Damage: Running the filter with either too little or too much ash due to misreadings can lead to long-term damage to the diesel particulate filter (DPF), the engine, and related emission control systems [1].
Ultimately, the accuracy of the differential pressure sensor is critical for the proper operation and maintenance of systems that rely on ash loading data [1]. Regular calibration and maintenance of these sensors are essential to ensure efficient operation and compliance with emission standards.

This is the last part of the Algorithm

M * T * R M = Exhaust gas mass flow upstream of GPF
T = Temperature of exhaust upstream of GPF
___________ R= Gas content of exhaust Gas

PSTAT + Ap1,f
PSTAT = Static pressure upstream of filter (stored static offset created for the differential pressure sensor).
Ap1, f = The first filtered differential pressure sensor reading.

Whats funny is that when we recently looked at one of our vehicles that had the modified filter fitted, we monitored the oil ash % and sensor reading information from the Dealer and we found something very unusual.

Before this vehicle had its filter fitted, we managed to get 5 readings of the sensor, along with the oil ash percentage information.

Oil ash percentage Differential pressure hPa
86.27 2.32
89.80 2.65
100.00 2.32

We had a new differential pressure sensor fitted before the filter was fitted.
83.14 2.65 before
83.14 4.23 after

After the modified GPF filter was fitted, the car went back again for two more oil ash checks.
45.49 2.65
47.06 2.32

Well, we can see a trend here, these readings are impossible, unless the ALGORITHM is designed this way, or its faulty.

Its quiet obvious that the Dealers and Porsche Technical are ignoring these inaccurate sensor readings, which must be causing this fault to happen.

Also when these sensors are replaced they cannot be adapted to the DME, more like a plug and play situation, that will not help either.
So the DME doesn't know a new sensor as been fitted, and the old sensor data is still in the DME.

So no calibration carried out on a part thats critical to the ALGORITHM function in determining Ash loading of our filters.

These differential pressure sensor readings must be the cause of this issue, its certainly not the Modified GPF.

Remember we have never seen a soot differential pressure reading high enough to trigger the soot warning information on the dashboards of any of our faulty cars.

This by design is not correct, the Dealers and Porsche will not answer our questions on why is this soot regeneration function is not working correctly.

And why nobody has ever seen it working.

Yet its fundamental that it does work correctly, we know the ASH is not real, we have never seen any soot in our cars. But we have this ASH % to deal with, that puts on the engine light between 90 to 100%, that will at the time of an MOT test, fail your car.

How long have we got to wait for this fault to be fixed.

Dave

 

[Scrounger]

Dave, I'd be interested to see the stats on build year, GPF failures and engine displacement (that you're aware of) that prospective buyers or owners may find useful. I'm not sure if it's relevant but also if there are more Caymans than Boxsters or 911s.

Dan

 

[Cyclemotor1958]

Hi Dan

Without prejudice

They are mainly 2019 Cayman 2.0 cars with the exception of Cayman 2.0 2023, and a Boxster 2.5 2022.

List below.

Cayman 2.0 26 vehicles
2. 5 3
Boxster 2.0 3 vehicles
2.5 2

Remember only 13 of these cars had new modified GPF filters fitted, paid for by Porsche, after we intervened.

Sadly 8 of these vehicles have been sold due to the oil ash levels coming back, and regarding the other 5 vehicles, we are still waiting for an answer from Porsche on what to do next.

Will we be chasing these Dealers for confirmation of what they are going to do next.

So far, on 2 of our vehicles, we have been told recently by Porsche that these returning oil ash levels are ok, and no further work will be carried out.

Obviously we will be having these cars checked again by the repairing Dealers to monitor these Oil Ash percentage levels that are not correct, bearing in mind they have had new filters fitted last year.

It took around 6 years for these cars to build up the Oil Ash level, that puts the light on, and leaves the DTC P242F, (oil ash load exceeded). Some of these repaired cars are in a situation that they have more than 50% oil ash readings so far.

These are all documented on a database, but there was probably more I dealt with in the beginning.

Dave

 

[Scrounger]

Thanks Dave. Is there a correlation in chassis number, as in are they within say 1000 on the last 4 on the VIN? Just thinking it may be possible to narrow down the issue to a faulty batch of DMEs or GPFs which relate to a VIN window.

Dan