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Cayman 718 GPF Failure

Porsche introduced GPF for the 2019 model year with production beginning in September 2018 (see Interestingly, the parts list for the 718 shows the oil spec for all models changing in May 2018:
718 oil callout in parts lists.jpg
The above is from the latest 718 parts list available from the Porsche UK website (dated 19.07.2018). Although the particulate filter is mentioned on this page (section 104-005 Engine Lubrication), there is no other reference to the filter anywhere else in the file.

From Dave's earlier posts, it seems like there have been a number of revisions to emissions related parts, and possibly software, subsequent to the introduction of GPF. Because emissions failures are environmental rather than safety related, there would be no need for a recall notice in many markets. Extended warranty claims are not assessed or paid by Porsche themselves, but by the insurance underwriters for the plan. I doubt if they will pay out on failures due to a design defect, leaving Porsche themselves to fix the issue, or not in this case.
Hi Ian
Just found this posted a month ago, from a MG driver who is on YouTube. His vehicle displayed a gpf warning light which he had not seen before. He checked his handbook for information, found this info, took his vehicle on the road carried out the instructions and guess what the light went out.
What a shame our cars seem not to display the correct warning light.
Again I have checked other manufacturers that have managed to get this software right, so why can’t Porsche.


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Hi me again
Came across this from June 2018, it's interesting, regarding the release of the new cars with GPF fitted.
Lots of manufacturers had to put in place quickly, new exhaust emission systems to comply with the more stringent emission regulations regarding EURO 6.
If you read the paragraph above consumption data, it seams to illustrate the pressure that manufacturers were under. And the reference to test benches could be a clue why this latest technology may have needed more time to prove it can cope in with our driving needs.
Maybe it's me thinking this, but what I have seen over the last 6 months suggest that we are having a real problem with these cars.

It almost sounds like commercial pressure to deliver cars caused Porsche to take a gamble and release new tech to production that was not fully tested and debugged, leaving customers to complete the testing. When problems arise, commercial pressure means no support for affected customers.

This sounds like it could have the potential for a class action against Porsche.
Unfortunately we do not seem to be able to make progress on this, largely through lack of evidence. Dave has done a considerable amount of work and helped a number of members - thank you so much Dave.

Whilst we believe that it is an issue that potentially affects 2019 2.0 liter cars, and there is discussion on forums etc. we still only have 5 or 6 actual examples. The nearest we have to Porsche accepting any responsibility relates to false information given at sale (111 check etc.) and other reasons whereby the fault was 'oroved' to exist when the car was sold by the OPC, The couple of instances where new GPF's are known to have been fitted look like they might be clogging up again, but it will be a while until this is proven one way or another. Dave has asked on here, and I have raised the matter in Porsche Post, but no-one has come forward.

Are there instances where the GPF warning light has come on? Not to our knowledge. Is the warning system fitted to these cars and active? Don't know. Has anyone had their AOS replaced (with a different part number)? Ditto.

So the Porsche official stance is that there is no problem as there are no warning lights shown. If the GPF gets clogged. they have no position on why it is getting clogged, other than a suggestion that driving patterns may affect it. They do not get paid to diagnose anything and they do not generally test the AOS function. As far as Porsche is concerned, if a GPF gets clogged, the answer is to replace it. 'We see no issues'

We therefore comme back to lack of evidence. Why are owners not shouting about the issue? We have not heard of it affecting Boxsters.? What is different about these 2019 cars?

Some thoughts:
- Some may have been fixed under warranty or sale terms, so 'nothing to shout about'
- Others may have sucked up the big repair bill or got other contributions.
- Indies have been able to clear clogged filters so nothing to report

It is easy to understand that, if an owner has had a problem and got it sorted to his / her satisfaction, they may not wish to broadcast it.

Dave has two new cases in the past week. Maybe the cars are getting to the point that we might see more. If we could get up to, say, 20 we might be able to get Porsche's attention and we might have some evidence to support our case. Meanwhile it is difficult to see what we can do other than wait and listen to what folk are saying.

We hope that we can get more real data.
Hi its me again,

Another two people this week joining our cause, they have both been told they need to raise at least £7,500.00, to sort out a little yellow light on the dashboard.

Lots of phone calls back and forth, trying to help these two come to terms with the position they are in.
Having been working on this project since last November, and collecting lots of information along the way, I would like to share my findings.

All these cars have the same issue, no advanced warning light comes on the dashboard to tell the driver to initiate a regeneration, as the drivers manual states.

The oil ash load K231 is measured on these cars, why is oil mentioned, it shouldn't be in the GPF

Took this information from a recent vehicle with an 100 % oil ash load.

The exhaust temperature upstream, before the GPF, T251 was 8.91 degrees C,?
The exhaust temperature in the filter T255 was 381.60 degrees C.

After monitoring two cars, that have recently had a new GPF fitted, both T251 and T255 had very similar temperatures, usually showing, around 350 degrees, give or take, around 25 degrees difference between the two.

Also found, when checking the readings on the differential pressure sensor current value K251, its not uncommon to see a 0.00 value.

This 0.00 value on the pressure sensor, means that no information regarding the soot and ash loading is being reported to the engine control unit.

On a working differential pressure sensor with a GPF filter not over loaded, and checked on tick over, you would find a reading around 3.8 hPa.

Could it be that these sensors are causing the filters to fail, the two pressure pipes can become blocked, could be leaking, also heat in the engine bay can affect the readings from the sensor.
And its not uncommon for electrical interference, from other electrical components affecting the signal back to the engine ECU.

Also when checking on the sensor used on these cars, the sensor part no PAE 906 051D was superseded around April 2121 , was the supersession an upgraded part ?

Its quite simple to check these sensors, to ensure all is well, could they be checked as part of the service, along with GPF in and out temperatures, and oil ash load measurement levels.

Another thought, all the cars I have looked at, it seems that nobody as reported a lack of performance from the cars, even though the oil ash levels are at 100%.

If the ash contamination is blocking the exhaust then this would force exhaust fumes back into the engine causing even more problems.

Again have we checked for exhaust back pressure, with a vacuum gauge, before the GPF is removed.

Could it be that the information on the GPF report is not correct, and this maybe condemning the GPF, after all as anybody in a Porsche dealer service department , smoke tested these exhausts, to prove they are indeed blocked with ash.

The £50.00 reward I posted out on my last post to anybody who has seen the particulate warning light coming on, seems not to have worked, just increased it to £100.00.

I am still looking at the possibility of the AOS causing oil contamination of the GPF, bearing in mind this part was also superseded on the 1st April 2020.

And what's amazing is, we have no reports of these issues on the 2020 vehicles, and also the Boxster 718 what's going on.

Well that's enough from me for now.
Well done for persisting with this issue Dave despite the apparent lack of progress.

It seems that you’re confirming my thoughts which are gravitating to potential issues with the electronic monitoring system(s) not triggering the necessary warning to the driver to carry out the necessary regeneration process.

I do find it odd that no Boxster owners have approached you reporting the GPF issue. I can’t believe that the problem is specific to the earlier 718 Caymans, although according the How Many Left website more base Caymans were registered between 2018 and 2020 [35 versus 24], although not all will have a GPF fitted.

Please continue to keep us updated.

If Porsche can give a reason for the superseded part then there may be grounds for a claim and maybe a refund for those that have already paid out due to the original part not working correctly.

Chances of them doing that are pretty slim however it would be interesting to see how a Court would rule if it ever got that far.

This light needs to come on and be seen, then all this trouble with our cars will go away.
Fingers crossed


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Hi everybody me again,

The standard answer from Porsche Customer Care when asked, why has my GPF failed is the following:
Also they send an instruction page from the drivers manual, detailing how to drive the vehicle to initiate a regeneration on the road.

They are advised from the technical department that a warning light will only appear if soot builds up and requires cleaning through the system.

If it is a build up of ash, then this would result in the engine management light appearing

Just had a look at a current Vehicle Analysis Log, where the GPF filter needs to be replaced, due to the oil ash load measured at 100%, reference number for this measurement is K231 on the report.

On these Vehicle Analysis Log reports, it only shows two references to soot, our report shows this information below.

1. K211 particulate filter bank 1, soot load calculated, ours showed 3.92%
2. K221 particulate filter bank 1, soot load measured, ours showed 0.00%

On a new GPF filter we had fitted recently, that had covered only 1,000 miles we found the following readings, The K231 oil ash load measured reading was 38.4% at the time.

1. K211 particulate filter bank 1, soot load calculated, ours showed 0.00%
2. K221 particulate filter bank 1, soot load measured, ours showed 4.71%

If Porsche Technical are saying that the warning light will come on when the soot load builds up to a point the car needs a regeneration, how can it.

Why are these soot calculation and measurements, so low in percentage terms.
It clearly isn't working as it should, as the GPF filter only alerts the driver when the EML light comes on.
This depending on the oil ash measured %, would mean either an attempt to carry out a regeneration, or worse case, replacement of a very expensive GPF filter.

I have plenty of these Vehicle Analysis Logs now to be confident that we are on the right track, all we need is Porsche Technical to act on this information.

Sooner the better please.

Cyclemotor 1958
Hi Dave, great work as always.

I think more and more 2019MY will start to come forward with this issue and it's about time Porsche took notice! I am convinced they know it's a problem as more OPC are replacing them at their cost....why would they do that if it's not an issue??

I really appreciate the help you have given me in avoiding the £7500 bill to replace the GPF, without your help it would have cost me dearly, and I'm sure it's the same for all the others you have helped.

Keep up the good work and if I can help in any way just reach out.


Hi Mark,
Just another update.

We are still looking for the GPF warning light to show its self on the dashboard, this light should warn the driver to carry out a regeneration on the road, as its written in the drivers handbook.

Also we are seeing quite a few AOS, (oil / air seperator) being replaced at the moment, especially in the independent workshops.

As we know when these seperators start to fail, the vacuum increases in the engine and pulls oil droplets into the cylinders producing even more soot, which can overload the GPF.

These soot emissions can be contaminated with engine oil, which helps build up the ash levels in the GPF, which then pushes us towards the 100% oil / ash levels.

Which eventually turns on the engine management light, and a new GPF having to be fitted.

Could the AOS vacuum levels be checked more often, bearing in mind this part is not monitored electronically, by using a manometer.

Just been involved with a AOS failure on a 2019 vehicle with less than 20k on the clock.

We know that we need more oxygen to increase the exhaust temperatures to carry out a regeneration, usually above 600 degrees.

Currenty working on an idea that we inject oxygen into to the GPF, monitored by an exhaust temperature sensor in conjunction with a warning light, which in theory could work.
Shouldn't be to hard in a workshop environment to adapt a car and see if at the right time, oxygen injected into the GPF had the desired affects.

Has we know other manufacturers are having issues with regeneration at the moment on petrol vehicles,so if we did not need to drive these cars miles and miles to put this light that could be a good thing.

Remember when diesel cars had to have dpf filters first fitted, it was a struggle but we got there.
As we know petrol cars with GDI engines fitted, (gasoline direct injection engines) are very particulate polluting, hence the fitting of GPF filters.
So It could be that the GPF systems first fitted way back in 2019 will need to be modified to cope with our way of driving.
Look at what as been achieved with electric vehicle technology, we just need to get on and get this sorted.

Cyclemotor 1958
Just read all this thread, fabulous solid investigation, most impressed.
Made me flinch when I saw AOL written as these things have tormented me on my 2009 987.2 and still do.
Why Porsche are so poor as sorting these issues is beyond me, maybe the engineers are diverted to count the profits now?
Just how to get under the hard shell skin of Porsche in Germany will be an even bigger issue, doubt anyone will do that via the UK operation But the lady who oversees the UK is in the front of Porsche Post, could help?

Cyclemotor, please keep going!
I agree with all that Graham, and a top-notch investigation by Dave. All credit to him for his persistence in trying to get to the bottom of this problem in order to try to save owners whose 718 has suffered a GPF failure a significant expense.

Since the problem appears to afflict the early cars you have to suspect that maybe Porsche put this into production somewhat prematurely to meet an immediate requirement and subsequently got on top of it, maybe with a more robust AOL design, although that doesn’t really address the point - as far as I understand it - that the problem appears to occur only on the 2.0L cars. As far as I’m aware the 2.5L uses a slightly bigger [variable geometry] turbo with a lower boost pressure, and I believe that it’s location is slightly different compared with the smaller engine car, so on the face of it it’s difficult to understand why only the 2.0L cars experience the problem.🤔

Please keep us updated on progress Dave.

Hi everybody, me again

I sent out my AOS tester yesterday to a 718 owner in Berkshire to check the AOS vacuum reading as this vehicle is currently having issues with the GPF.
As you know I am 100% convinced that these AOS parts could be contributing towards the GPF premature failure.
Pulling together lots of data at the moment to support this, have friends in independent workshops also assisting me.
Will keep you informed
Thanks for the update Dave.

With the data you have at the minute, is there any link to model year or mileage with cars that are experiencing the GPF failures?

Just a thought Dave but to obtain some more general information for your database you could take your AOS tester along to one of your local Regional meetings [other Regions too?] to do some measurements. There are bound to be a range of vehicles … 9x7, 9x1, 718, etc.

Considering all the expensive kit that Porsche insist the dealers have to purchase you’d think that a relatively inexpensive manometer would be no-brainer given the apparent frailty of their AOS component!🙄

Keep up the excellent work!

Hi Jeff

Thanks for your comments

Regarding our AOS issues, currently advising an American with a 718 Cayman 2018 with 55k, with excessive white smoke on start-up.

On the 718 Forum, if you search (718 white smoke), to will see our recent conversations.

Also if you type (How to test your AOS) in YouTube, this shows you how a monometer can easily check the reading on these cars.

Bearing in mind this test was for earlier cars, which generally run between 4 to 6 inches of water
Gen 2 cars generally run between 14 to 16 inches of water.

On the 2019 cars with GPF issues they measured around 30 to 32 inches of water on the original AOS.

On the last AOS replacement I was involved in, when the AOS was tested with a monometer, it couldn't read a value, it was that bad, it was off scale.

These manometers generally measure up to around 50 inches of water maximum.

This is the reason why I continue to push on with this information, these AOS parts should be tested every time the car goes into a Porsche Dealer, or Porsche Specialist.

This is a really important engine part, that can cause a lot of trouble.

Cyclemotor 1958

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