Cayman 718 GPF Failure

[Motorhead]

One question, we all subscribe to this club. What is Porsche Club GB doing to help? They must be aware of your fight to help us all, what have they offered in support and surely they must have contact at Porsche reading to facilitate a meeting or at least contact?

That was done a while ago - probably you’ll find reference to it somewhere in this thread - and I think involved Dave, John Dickinson the Cayman Register Secretary and a Club official who, I seem to recall, wrote an article for PP. Someone with a better memory than mine should be able to point you in the right direction.

All to no avail unfortunately!

Jeff

 

[Cyclemotor1958]

Hi Tony,

Sorry Ive been discussing this with a few of my technical mates, and they can't believe they will not do a back pressure check.

When you think about it, is bloody ridiculous that they think they can get away with not doing this important check.

Infact this test is deliberately not done, thats been obvious for a very long time.

They know that no pressure is there, so whats their argument for not doing the test.

The truth will come out on this eventually, and Porsche will have some explaining to do their customers.

Just think of the cars that have had their original GPF systems removed and replaced with none approved exhaust systems because they couldn't be bothered to do the diagnosis correctly.

GPF built cars without GPF filters, absolutely disgusting behaviour.

Please keep us in the loop regarding the checks they are going to do, hopefully they won't be removing your engine to have a look for possible internal signs of oil consumption.


Dave

 

[Cyclemotor1958]

Morning Jeff,

Just to put the record straight, John and I had nothing to do with the Porsche Post magazine article regarding this GPF problem.

We worked on our own article that unfortunately reflected the real issues on these cars, and certainly would not have been allowed in the Porsche Post magazine.

When the Dealer Principal gets his monthly copy of this magazine, its then
made available for customers to read in the Sales and Service reception areas.

So you can see that this type of news would not have been welcomed, and certainly not by prospective customers.

Dave

 

[Motorhead]

More than happy to be corrected Dave. So much has happened in more than 3-years since this thread was started that it’s difficult to keep track of it all!

As I’ve said before - probably many times! - I admire your persistence in the face of Porsche’s continuous and inexcusable stonewalling when simple remedies are blatantly obvious. Astonishing behaviour for a company which traditionally has prided itself on engineering excellence.

Jeff

 

[JohnCRS]

For those of you who may not have been in on this from the beginning, this is the article that was published in Porsche Post in the April 2025 edition, page 74. https://issuu.com/porscheclubgb/docs/porsche_post_digital_march_2025?fr=xKAE9_zU1NQ
For the record, I built on the work that David had done and provided information to the then editor Richard Gotch. He did further research, putting together a great explanation of the issue. Whilst neither David nor I had any influence on how the story was written, we were happy with the outcome as it asked key questions, why is this happening and what are Porsche going to do about it?

This is now my speculation of course. There was no response. to the article. Despite attempts by the club at all levels, Porsche simply will not engage in any conversation about this. We have no leverage. Their instructions to OPC's appear to mirror this and I suspect the refusal to do a back pressure check is likely to be in response to such instructions. As far as Porsche are concerned 100% ash load = new GPF required. (If you don't like it, go away.) They did the same with bore score, attributing it to the way the cars were driven and maintained, dealing with each case individually and ultimately wearing the market down as the cars were out of warranty. Who expects porsche to deal with bore score now. They did the same with early PDK faults - the only solution to any problem being a new gearbox.

There is almost a cycle to these things
- Deny a fault exists at anything other than a one off basis
- Offer an expensive replace only solution on an individual basis
- Block parts supply to anyone trying to offer an alternative solution
- Once cars are out of warranty and of no value to the Porsche network, accept that alternative solutions will be developed.

I think we are probably at stage 2 to 3 now with GPF. And to be clear, we know the cars run fine with the supposed 100% ash load, we just need to get the light out.

 

[Cyclemotor1958]

Hi Jeff,

Thanks for your kind words, its appreciated, this journey started over 3 years ago and we have collected so much information along the way.

We have proved beyond any doubt that replacing the original GPF filters on these cars was a waste of time.

We knew that if we pushed on with our challenge against the software measured ash % value, and the lack of physical pressure in the GPF, we would succeed.

Well, we have succeeded, and to prove this, just look at Tony's conversation he had this week with his Dealer.

He asked them about a back pressure check, and they said they weren’t authorised to do a back pressure check, so they wouldn't do one.

What they are going to do is carry out checks on the engine for possible signs of internal oil consumption, which over a period of time could cause ash load in the GPF to increase.

Well over 7 years in and they are still using this same diagnostic avoidance tactic.

This fault was on these cars durring the first year of manufacture, the internal memo backs this up.

Has we have said this before, we have some much proof to support our claims, its unbelievable that we are still trying to get them to do the back pressure test.

So I enclose photos of 3 documents that support our claim that these filters are not blocked with Ash.

First document is from the 3rd car I dealt with which was repaired by Porsche Reading case number 8000244324.

It took over 5 months to get the new modified filter authorised the actual date was the 25th June 2024.

After the repair Customer Care sent this email to the customer.

You can see they identified the fault to be that of a manufacturing defect.

At the same time they said they were unaware of an inherent fault with the GPF's on their vehicles.

2nd document is a recent Dealer technical report that was sent to the customer after he challenged them regarding the none existent differential pressure sensor reading.

If you read the top section half way down, it says.

The description of the fault code is that the ash load is to high, not that the particulate filter is blocked, this is from the Technical Department.

If you continue to read on it explains these other checks that Tony's car is having right now.

The lower section contains the information I gave to to the owner to give to the Dealer to send on to Technical Department.

Whats really sad is that this technical report belongs to another owner that purchased his car from new from the same Dealer that Tony bought his car from.

He had over 75% of ash present at his first service with 11,713 miles on the clock.

The Dealer carried out a regeneration which didn't change the ash value, and it had a differential pressure reading of 0.00 hPa.

Funny thing, they never told him about the ash level, or the regeneration they carried out.

If they had, they could have replaced his GPF under the manufacturer's Warranty.

This owner contacted me last July for help when his light came on, the Dealer has consistently knocked this customer back.

He has managed to get a contribution from the Dealer and Porsche, but his contribution is still considerably very high.

He has asked them lots of times for a back pressure check to be done, and he would pay for it, and of course they refused, just like Tony's case.

So whats the difference between these two cases, its the same fault afterall.

Porsche Technical have been involved in all these cases yet, they don't believe that a differential pressure sensor thats showing no pressure is something to worry about, and any further checks to see if the sensor information is corrupted are not required or relevant.

3rd document is a Technical bulletin that was released last year across the pond, that landed on the desk of the NHTSA.

It explains that the correct engine oil is critical to the ash accumulation of a GPF filter.

Now the difference with the Technical guys over the pond is that they know that the accumulation of Ash in the GPF affects the exhaust back pressure and reduces the amount of soot that can be stored before requiring a regeneration.

When you read at the bottom of this document it says in bold text that using unapproved engine oil can overload the GPF in as little as 1,000 miles.

This bulletin came out 4 days after our internal memo came out last year.

Now on our cars we never, ever have ever seen a soot loading message, or light before our Ash warning light comes on.

And we have never seen any soot values present when our Ash 100% DTC P242F is present.

MANUFACTURING DEFECT springs to mind.

Sorry to go on but, we need to go on.

Dave

 

[Cyclemotor1958]

Sorry John,

I was working on my post while you sent yours, brilliant post, you have summed this situation up in a few words. When you get time could you please give me a call.
Kind regards
Dave

 

[Cyclemotor1958]

Morning Guys & Girls

I found this post from 3 years ago that really hits home how bad this problem is on these cars, and we are still trying to sort it out.

We have three vehicles with this same issue in our local Porsche Dealerships within the same Dealer group.

The first car has been waiting over a year to get authorisation from Porsche to cover this repair 100%.

The second car is Tony's car, thats currently having the Porsche Internal Memo checks carried out.

And the third car, hes been waiting weeks for his Dealership to ring him back, to book his car in for a GPF back pressure check.
He's contacted them many times, but nobody will ring him back.

This is the post below.

I've actually never posted in a single forum in my life, but I've recently had an experience which I felt needed to be shared - edven if nothing further comes from it, if it raises a bit of awareness, then that'll be good enough.

I'm just an average bloke, who worked hard and saved, and was extremely proud to walk into Porsche Portsmouth (UK) and buy a Porsche Approved-Used 718 Cayman (Base Spec, 2.0l 4-cyl, manual) in August 2022. I'd done my research, bought a lovely and clean 2019 model, with just over 15,000 miles on the clock for about £45,000.

I thought going down the Approved Used route would mean I would certainly have a few years of trouble free motoring. Porsche tout an extensive multi-point inspection as part of their approved used scheme, which thereafter is still covered by a comprehensive 2 year warranty and assistance programme, and generally only appl;ies to cars which have alwasy had a full Porsche main dealer service history from new.

After around 10 months of ownership, a warning light came up on the dash, saying 'Engine Control Fault. Contact Dealer. Driving Permitted'. I rang my local dealership, who advised the best course of action was to call Porsche Assist, who would come out and diagnose it; if needed, they'd organise transport to a dealership too.
At this point, I wasn't at all worried, as I knew I had my approved-used warranty.

The Porsche Assist technician advised it was something to do with the DPF/GPF. At this point, I hasten to add, I'd only covered 1500 miles since purchasing the car. All my journeys were around 50-75 miles each time, and usually driving a fairly 'spirited'.

It was taken to Porsche Cambridge, who advised the GPF was full of ash, and the complete catalytic converter had to be replaced. I was then told, this was a 'fair wear and tear item', and I had to foot the bill.

A reminder - I purchased the car for £45,000, and had covered 1500 miles. I was now being asked to pay a further £6,538 for a new catalytic converter and fitting.

Needless to say, I was so upset, and completely furious. I knew that I had absolutely not filled up a GPF in 1500 miles of use; and bearing in mind that, I wanted to know why the dealership's 100+ point inspection hadn't flagged it as being nearly full of ash and rectified it prior to me purchasing the car.

I went back to the original dealership and raised my concerns, who agreed this wasn't fair. I was told to raise a case with Porsche UK Customer Interaction Centre (PCIC), to get it escalated.

I did just that, and raised a case. Without boring anyone with unnecessary back and forth; what ensued was 7 weeks of arguments. That required 42 separate telephone calls to get sorted. PCIC returned barely any of them, both dealerships were very good to be fair, but their powers are limited.

Throughout all of this:

• Technicians at my local dealership confirmed it was not my fault, and this should be processed by Porsche as a Warranty claim. That claim was denied by Porsche UK.
• Technicians at the original dealership also confirmed it was not my fault, and should be processed by Porsche as a Warranty claim. That claim was denied by Porsche UK.
• Porsche Care UK also agreed it was likely not my fault, and tried to negotiate with the warranty administrators. That claim was denied by Porsche UK.

The end result was a contribution from both dealers, and a 'goodwill' contribution from Porsche Care. I had to pay the balance.

So my warning to prospective owners is this - the approved used scheme is basically a marketed fabrication - there's a lot of exclusions it seems. I did not expect tyres or brake pads to be covered. I did expect major exhaust components to be covered. This was never communicated to me at the time of purchase. Bearing in mind the cost of the part alone, it should be made crystal clear.

I'm back to enjoying my 718 as I should have been, but I have lost all confidence in the brand, and their service. I have submitted an official complaint to Porsche, and additionally the Financial Conduct Authority and the Motor Ombudsman - they are evidently mis-selling the warranty product, which just isn't fair.
I've never done this with anything I've ever bought in 31 years of being alive, but I was so upset by all of it, and I am not willing to let it slide.

So if you're thinking of buying approved used, get a technician to go through all of that inspection report with you line-by-line; being 'that customer' in the dealership may make you feel a little demanding, but it may just serve to protect you.

I hope none of you ever have the experience I have - and happy and safe driving to all of you.

So three years on and our Dealers and Porsche are doing their best to damage the buying and owning experience of these great cars, have they not learned anything from this situation, but we have.

This is now surley over, no pressure, no blockage, no need to fit these modified filters, no need to carry on with this pretence.

Dave

 

[911hillclimber]

What a sad situation all round.
Did you get to know the condition of the car after the new filter was fitted and miles after?
Just as well Porsche are going electric still, real engines are outside their capability, or that good Porsches are based on AUDIs!

 

[Cyclemotor1958]

Hi 911hillclimber,

No sorry this one unfortunately slipped our net, and it would be good to catch-up with this quy, will have a look.

A software adjustment shouldn't be out of their capability, they have done a few in the past, like all other manufacturers have had to do with the new emission requirements that are required to clean up our air.

What Porsche and their Dealers should do is return the money they have taken from the owners of these cars, who bought these vehicles and had to endure this major fault, and are still doing so.

It would be a significant act of good will and could possibly rebuild confidence between customers, the Dealers, and the brand.

We hope to get more backpressure tests out on this forum to drive home the importance of this simple check.

I would advise any Cayman, Boxster 718 owner with the 2.0 and 2.5 engine to get their Dealer and Independent garage's to check their GPF ash % and if it doesn't look right, to go and speak to their nearest Dealer and ask them to set up a case with Porsche.

Hopefully this would stop our owners selling these cars because of this software issue before Porsche have a chance to fix this issue, which would definitely keep them in these cars.

Fingers crossed
Dave

 

[718touring]

Hi 911hillclimber,

No sorry this one unfortunately slipped our net, and it would be good to catch-up with this quy, will have a look.

A software adjustment shouldn't be out of their capability, they have done a few in the past, like all other manufacturers have had to do with the new emission requirements that are required to clean up our air.

What Porsche and their Dealers should do is return the money they have taken from the owners of these cars, who bought these vehicles and had to endure this major fault, and are still doing so.

It would be a significant act of good will and could possibly rebuild confidence between customers, the Dealers, and the brand.

We hope to get more backpressure tests out on this forum to drive home the importance of this simple check.

I would advise any Cayman, Boxster 718 owner with the 2.0 and 2.5 engine to get their Dealer and Independent garage's to check their GPF ash % and if it doesn't look right, to go and speak to their nearest Dealer and ask them to set up a case with Porsche.

Hopefully this would stop our owners selling these cars because of this software issue before Porsche have a chance to fix this issue, which would definitely keep them in these cars.

Fingers crossed
Dave

How many cars that you know of have been affected by this issue?. All I am seeing is that it’s a few and there are quite a lot of unaffected cars out there. This is having an impact on values of none affected cars, as people are avoiding buying these. Mine has been faultless in the 18 months of ownership and 6,000 miles that I have done.

I should add it’s a 2020 model year registered October 2019 Euro 6DG

It would be nice to have an actual list of cars with build days to put this issue in perspective rather than taring all cayman and boxster with the GPF issue.

 

[911hillclimber]

^^ Quite correct, but the facts of the few will eventually tar the 'good-ones' just see the IMS bearing on 986's, seals, and a lot of other big-bill issues on these cars.

I would think selling a car with these images of faults with the IMS bearing done would enhance the sale of the car.

As/if these cars affected are sold on, the next owner will have the same issue and the misery is prolonged and the image expands to tarnish the good cars.

Why though are there good cars with not lights on and those with lights on and even after the £9K fix?

 

[Cyclemotor1958]

Morning Dale,

If you would like to ring me this morning on 07769 590119 we can have a chat about what we have been doing over the last 3 years if thats ok with you.
Kind regards
Dave

 

[Cyclemotor1958]

Morning 911Hillclimber,

Your absolutely right, in everything you have said its ridiculous.

Porsche could have brought out an upgraded IMS bearing but decided not to, you could only get the IMS bearing with a new IMS shaft. Durring my time they were about £850.00 + vat, and it needed a full engine strip to fit it.

When I started my job 8 years ago has a workshop controller at a local Porsche independent, I had no expectations other than curiosity.

I started in the motor trade around 1973, and after my apprenticeship started working in a Lotus service garage in Bradford, called Soutar & Rhodes.

I worked there for along time repairing Lotus cars, engine tunning, carburettor tunning, and running a rolling road, we also had a fully functioning engineering machine shop.

Durring that time, we spent many days at the Lotus factory working with the guys on the shop floor sorting out issues we were finding back at our garage.

My boss at the time, Paul Rhodes ran this business with a culture of, we can improve and fix anything, and the time to come up with an engineering fix will not hold us back.

In my 50 years in the motor trade this way of working has followed me in all the jobs I have had.

When I got into management I made sure in every workshop I ran, that we had a technical department that reported defects found in our workshop back to the manufacturer we were working with at the time.

This way of working built up a brilliant relationships between us and the manufacturer and allowed extra concessions other Dealers didn't get.

My point to this is, in our day if a manufacturer told us not to do something we thought was wrong, we would have done it anyway, and made sure that proof of what we had done was sent to the people who said it couldn't be done.

Yes this was in the 70s and 80s but things haven't changed that much.

So a few months into my job at the Porsche garage I asked how do the AOS fail on these cars, at the time it was 996 and 997 vehicles.
I didn't get an answer, so I cut one open, and found a hole in the vacuum diaphragm, and took photos.

After further research I came across a chap in America called Tony Callas, at Rennsport Porsche who kindly sent me information regarding testing the AOS with a manometer, he also sent me the vacuum readings for each of the models we were seeing at the time.

When I checked around in our area including our local Porsche Dealer and Porsche specialists to see if anyone was using this tool the feedback was nobody had heard of this way of testing.

So I personally purchased my own manometer and checked every car that came in the workshop and found lots of failing AOS faults on lots of cars.

Whats the point of waiting for the white smoke to appear, when you can fix this car well before the it fails.

So way back in 2023 when I was told about this GPF fault and started to investigate it, a failing AOS was my first thought, regarding premature ash buildup in these filters.

Over three years on and this manometer tool can be used to prove that the back pressure on these cars does not align its self with a GPF filter thats supposedly blocked to 100%.

Dave

 

[718touring]

Morning Dale,

If you would like to ring me this morning on 07769 590119 we can have a chat about what we have been doing over the last 3 years if thats ok with you.
Kind regards
Dave

I have been reading what has been happening over the last 3 years and a phone call at this stage is irrelevant to me.
thank you for your kind offer.

what I am wanting is it posted in here the true extent of the issue, ie as posted above how many cars affected and build dates.

That data should be a minimum seeing as we have quite a lengthy debate, this will be the 1040th post on the issue.

granted some are have issues a bit like the early days of dpf’s and all I’m seeing at the moment is the lack of real car numbers affected by this data.

this whole issue smacked of being blown out of proportion for the few affected thereby taring all as potentially the same?

 

[patersont718t]

I have been reading what has been happening over the last 3 years and a phone call at this stage is irrelevant to me.
thank you for your kind offer.

what I am wanting is it posted in here the true extent of the issue, ie as posted above how many cars affected and build dates.

That data should be a minimum seeing as we have quite a lengthy debate, this will be the 1040th post on the issue.

granted some are have issues a bit like the early days of dpf’s and all I’m seeing at the moment is the lack of real car numbers affected by this data.

this whole issue smacked of being blown out of proportion for the few affected thereby taring all as potentially the same?

if it wasn’t for this forum and Dave’s posts I wouldn’t have known about the GPF and how to fight the £9700 charge, but you have fair point, but asking owners to pay up to £9,700 for a repair that many believe stems from a manufacturing defect simply isn’t right. What’s even more frustrating is Porsche’s handling of the situation. In my view, it’s Porsche’s continued denial that there’s a wider issue that’s keeping this story alive. As more cars develop the same apparent defect, the number of affected owners will only continue to grow, making it increasingly difficult to dismiss as isolated cases.

If Porsche simply do the right thing the issue goes away.

 

[Motorhead]

^^^ This exactly.

Thankfully Dale has been fortunate to date that he hasn’t been affected by this problem, unlike those - many of whom are likely to be outside the Club and probably aren’t aware of this post - who have have been asked to fork-out an eye-watering sum by their dealers to get their car back on the road after what Dave has shown to be an incorrect diagnosis.

I speak as someone who runs an 987.2 CS and so thankfully I’m not affected by this issue, but in my view even one misdiagnosed case is one too many!

Jeff

Edit: For context I looked at How Many Left to check how many 2.0L 718 Caymans were newly registered. Dave will be able to tell us the period we’re looking at for the failures he’s seen, but if we just take the three years 2019, 2020 and 2021 there were 83 Base cars and 48 T cars registered, although there will be a few more Base cars which were registered from September 2018 when 69 cars were registered in that year. I can’t vouch for the accuracy of those numbers and of course I’m sure that there will be a similar number of Boxsters, but the numbers aren’t huge.

 

[Cyclemotor1958]

Hi Jeff and Tony,

Thanks for your thoughts on this subject, we always knew that the more we pushed in trying to work out this problem, their would be consequential damage to the image of these cars.

Up until we got sight of the Porsche internal memo, we had no idea on how many cars could be affected by this issue, but we learnt that two major defects on these cars was standing out.

The first was how the car reports the ash % content, and the second was there was no way on these cars to carry out any adaptation of the differential pressure sensor or the adaptation of a GPF filter.

These adaptations are fundamental to an emission controlled vehicle, and without them their would be a problem eventually.

We now have the knowledge to look at these cars and make a reasonable prediction on any car that trouble could be ahead.

Dale, wants to know how many cars have been affected we don't, we just need Porsche to own up to this fault.

The internal memo says it all.

Worldwide, and model year 2018/2019

It says if the engine light comes on, and the DTC code P242F is present your journey begins.

What the memo doesn't say is who pays for the checks and replacement of the modified GPF.

Enclose their memo again for your attention again, they need to tell us how many cars are affected, they caused this problem we didn't.

We naturally assumed that a modified filter brought out to fix this emission control fault would be covered by the manufacturer, when they started paying we appreciated it, they have now stopped.

Thats why we are repeating ourselves all the time, to convince them to do the right thing.


Dave

 

[Cyclemotor1958]

Hi Guys & Girls

Well, we've had a 2021 Boxster 718 2.0's backpressure checked with a manometer today, the car has done 43K.

Its been running around for more than year with the warning light coming on, and off.
The owner has been checking the ash reading on his car using his own diagnostic tester.

He carried out this backpressure check today with his ash load at 100%, and the usual not soot present.

Enclose a photo of his dashboard warning light on and message, also a photo showing no soot present, and another photo showing the measured 100% reading.

And the final photo showing the pressure reading taken from his manometer connected to the differential pressure input pipe to the sensor.

IT READS 0.028 KPA, IF YOU CONVERT TO HPA YOU GET 0.28 HPA, AND CONVERTED TO PSI YOU GET 0.00406105567.

SOD ALL PRESSURE AGAIN.

So this is another 718 model thats had a backpressure check carried out and there is no pressure, but its not a 2019 model, its a 2021 model.

This is why are Dealers are refusing to carry out this back pressure check, because if they did they would see that no pressure is in the GPF.

So no pressure, means no need to replace the GPF, if the exhaust tail pipes have no signs of soot, then the GPF is ok.

Unfortunately I have never been able to get Dealers or Porsche independents to do these checks because of a fear that any involvement with ourselves could possibly jeopardise their relationship with Porsche.

So we are getting our owners to carry out these backpressure checks.

With have sufficient evidence now that a simple backpressure check would stop the fittment of these modified GPF filters.

We will push on

Dave

 

[Cyclemotor1958]

Hi its me again,

Enclose below is a YouTube video showing why its so important to check the differential pressure sensor readings on a vehicle with a suspected blocked filter.

Sorry its a diesel car, but you can see how easy the backpressure can be checked.

This guy is brilliant and he explains this fault in a way thats easily understood.

Dave