Couldn’t agree more Dave. An AOS condition check every 2-years would go a long way to nipping in the bud any failures before they become catastrophic, especially on cars fitted with a GPF.
Jeff
Cayman 718 GPF Failure
- Thread starter Wrightrubber
- Start date
Couldn’t agree more Dave. An AOS condition check every 2-years would go a long way to nipping in the bud any failures before they become catastrophic, especially on cars fitted with a GPF.
Jeff
Maybe just change the aos at set miles at service, but I like the prevention is better than cure thinking.
Tedious job on the 987.2, hope it is easier on these later cars?
Tedious job on the 987.2, hope it is easier on these later cars?
Not sure if this is relevant to Dave's research, but this just popped up on Rennlist - a burnt out GPF on a 4.0 engine after 31k km:
CEL Code : P226D ( OPF KO )Time for Akrapovic Link Pipes - Rennlist - Porsche Discussion Forums
718 GTS 4.0/GT4/GT4RS/Spyder/25th Anniversary - CEL Code : P226D ( OPF KO )Time for Akrapovic Link Pipes - Hello all, so 31,000km on the car and it seems as though Ive burned through my OPF filter or at least on one side, I got a CEL ( No limp mode ) tonight after driving relatively normally and...
rennlist.com
"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."
This is a fascinating - and slightly worrying thread if you drive, as I do, a MY2019 2.0 Cayman. Try as i might I cannot see in my manual whatthe instructions are to initiate a regenaration on the road should it be necessary. Does anyone have these so that they can post them here for all to see ? Thanks for all the hard work, much appreciated !
Hi 70Coupe
I have a copy of the Porsche regeneration instructions from the handbook on WhatsApp, if you send me your mobile numer number,I can send them to you.
Regards
Dave
Cyclemotor1958
I have a copy of the Porsche regeneration instructions from the handbook on WhatsApp, if you send me your mobile numer number,I can send them to you.
Regards
Dave
Cyclemotor1958
Hi Guys
Hope you are all well,
Just had another Cayman owner contact me over the weekend with another GPF issue, same 2.0 and same year 2019, same fault code.
Have been looking at another Vehicle Analysis Log that reported a faulty GPF filter, and have broken it down to these separate sections.
K211 Particulate filter bank 1 soot load calculated 3.92%
K221 Particulate filter bank 1 soot load measured 0.00%
K231 Particulate filter bank 1 oil/ash load measured 100% (this reading condemns the GPF)
T255 Particulate filter bank 1 exhaust gas temperature in the filter, calculated 361.60 degrees
T251 Particulate filter bank 1 exhaust gas temperature, upstream of filter, calculated 8.91 degrees
K251 Particulate filter bank 1, differential pressure sensor, current value, 0.00 hPa
If you look at these actual values you can see that both the GPF filter temperatures, are calculated, not actual.
And the upstream temperature cannot be true, it means that if you touch the GPF at one side, it would burn your skin, and the other side you could put your hand around it.
Regarding the soot readings, we have been told that when the soot loading is at a high level the particulate warning light will come on, to instruct the driver to carry out a regeneration as per the handbook.
None of drivers have seen this warning light, they only see the engine management light come on.
In all the Vehicle Analysis Logs I have seen, the soot readings only seem to show one actual value, out of two, and they change.
These vehicles have 3 lambda sensors fitted to the exhaust system, and 1 differential pressure sensor.
There is no exhaust temperature sensor fitted to these cars, so how does the ECU know how hot the exhaust is at any time.
Bearing in mind we need around 600 degrees of heat to turn the soot into ash, how can this work with calculated and inaccurate temperature readings.
Could it be the these calculations come from the the readings off the differential pressure sensor, as this is the only one that reports a current value.
The differential pressure sensor tends not to show a value, if the oil ash load is around 100%
If this sensor fails to work, then the excessive soot load will take out the GPF.
Are all these GPF blocked, has anybody checked with a simple vacuum gauge to see if they are blocked, has no lack of performance as been reported in all the cars I have dealt with, yet they reading 100% measured.
Regarding my favourite, the AOS (air oil separator), this component can certainly take out a GPF filter, as the vacuum increases more oil droplets are sucked into the engine, which in turn creates more soot, and more ash.
This component is not electrically monitored, and is under the radar, if its not checked on a regular basis, by using a manometer, then no wonder we are having problems.
I believe that the reason we seem to be having issues on these cars 5 years down the line, could be the AOS.
And I believe that if the GPF control values made some sense, then things could be very different.
Any feed back from this post would be appreciated
Regards
David
Cycle motor 1958
Hope you are all well,
Just had another Cayman owner contact me over the weekend with another GPF issue, same 2.0 and same year 2019, same fault code.
Have been looking at another Vehicle Analysis Log that reported a faulty GPF filter, and have broken it down to these separate sections.
K211 Particulate filter bank 1 soot load calculated 3.92%
K221 Particulate filter bank 1 soot load measured 0.00%
K231 Particulate filter bank 1 oil/ash load measured 100% (this reading condemns the GPF)
T255 Particulate filter bank 1 exhaust gas temperature in the filter, calculated 361.60 degrees
T251 Particulate filter bank 1 exhaust gas temperature, upstream of filter, calculated 8.91 degrees
K251 Particulate filter bank 1, differential pressure sensor, current value, 0.00 hPa
If you look at these actual values you can see that both the GPF filter temperatures, are calculated, not actual.
And the upstream temperature cannot be true, it means that if you touch the GPF at one side, it would burn your skin, and the other side you could put your hand around it.
Regarding the soot readings, we have been told that when the soot loading is at a high level the particulate warning light will come on, to instruct the driver to carry out a regeneration as per the handbook.
None of drivers have seen this warning light, they only see the engine management light come on.
In all the Vehicle Analysis Logs I have seen, the soot readings only seem to show one actual value, out of two, and they change.
These vehicles have 3 lambda sensors fitted to the exhaust system, and 1 differential pressure sensor.
There is no exhaust temperature sensor fitted to these cars, so how does the ECU know how hot the exhaust is at any time.
Bearing in mind we need around 600 degrees of heat to turn the soot into ash, how can this work with calculated and inaccurate temperature readings.
Could it be the these calculations come from the the readings off the differential pressure sensor, as this is the only one that reports a current value.
The differential pressure sensor tends not to show a value, if the oil ash load is around 100%
If this sensor fails to work, then the excessive soot load will take out the GPF.
Are all these GPF blocked, has anybody checked with a simple vacuum gauge to see if they are blocked, has no lack of performance as been reported in all the cars I have dealt with, yet they reading 100% measured.
Regarding my favourite, the AOS (air oil separator), this component can certainly take out a GPF filter, as the vacuum increases more oil droplets are sucked into the engine, which in turn creates more soot, and more ash.
This component is not electrically monitored, and is under the radar, if its not checked on a regular basis, by using a manometer, then no wonder we are having problems.
I believe that the reason we seem to be having issues on these cars 5 years down the line, could be the AOS.
And I believe that if the GPF control values made some sense, then things could be very different.
Any feed back from this post would be appreciated
Regards
David
Cycle motor 1958
Thanks for the update Dave. Some very useful information and insights there, and I agree with you on all points.
Some very puzzling and scarcely believable data in there, both measured and calculated, doesn’t give you much/any confidence in Porsche’s monitoring methodology. How can an up-to-temperature exhaust system have an exhaust gas temperature less than 9 degC?
I’m very much with you on a failed or failing AOS being a possible cause of GPF failings, especially because it seems that it’s an unmonitored device, and Porsche dealers have no means to measure or gauge its performance other than by observing clouds of smoke!
Please continue to keep us updated.
Jeff
Some very puzzling and scarcely believable data in there, both measured and calculated, doesn’t give you much/any confidence in Porsche’s monitoring methodology. How can an up-to-temperature exhaust system have an exhaust gas temperature less than 9 degC?
I’m very much with you on a failed or failing AOS being a possible cause of GPF failings, especially because it seems that it’s an unmonitored device, and Porsche dealers have no means to measure or gauge its performance other than by observing clouds of smoke!
Please continue to keep us updated.
Jeff
Thanks Jeff,
Currently sending out a manometer tomorrow to check the vacuum reading on a vehicle that's having GPF issues.
Pulling together some real time information on the AOS, function, will keep you all informed as we go.
Dave
Currently sending out a manometer tomorrow to check the vacuum reading on a vehicle that's having GPF issues.
Pulling together some real time information on the AOS, function, will keep you all informed as we go.
Dave
Dave. Thank you, once more, for all the work you have done on this and especially for the direct support you have given to owners reporting this issue. You have saved them many £thousands.
It would be good if we could get an official or unofficial response from Porsche on numbers like those you have posted above. As you say, they don’t make sense - tell us what is really happening. But the OPC’s just quote the official line which is to ‘blank’ the issue. Having said that, they are obviously involved with some of the individual cases you have dealt with and sanctioned no cost repairs. But, unless there is a wave of claims, it is unlikely to make headlines.
Oe important point out of this is that the AOS looks to contribute to this problem, failure resulting in blocked GPF’s. A blocked GPF is not covered under warranty. The dealers have no procedure to test the AOS which, if faulty, would be covered by the warranty. If the AOS fails and causes GPF failure, the whole cost would be a warranty item.
At present it all comes down to the fact that, as a result of your work Dave, anyone facing a potential big bill for anything AOL or GPF related should get in touch via pm on here or email Cayman@porscheclubgb.com. It could save you a lot of money.
It would also be good to hear of any related issues that owners have had resolved independently. The more information we can gather the better.
It would be good if we could get an official or unofficial response from Porsche on numbers like those you have posted above. As you say, they don’t make sense - tell us what is really happening. But the OPC’s just quote the official line which is to ‘blank’ the issue. Having said that, they are obviously involved with some of the individual cases you have dealt with and sanctioned no cost repairs. But, unless there is a wave of claims, it is unlikely to make headlines.
Oe important point out of this is that the AOS looks to contribute to this problem, failure resulting in blocked GPF’s. A blocked GPF is not covered under warranty. The dealers have no procedure to test the AOS which, if faulty, would be covered by the warranty. If the AOS fails and causes GPF failure, the whole cost would be a warranty item.
At present it all comes down to the fact that, as a result of your work Dave, anyone facing a potential big bill for anything AOL or GPF related should get in touch via pm on here or email Cayman@porscheclubgb.com. It could save you a lot of money.
It would also be good to hear of any related issues that owners have had resolved independently. The more information we can gather the better.
Thanks John for your kind words,
We just need to push on with this.
Its unacceptable that these Porsche drivers are being told by the dealers that they cannot do half hour journeys in these cars.
We are still waiting for a response from Porsche Technical to show use how the GPF regeneration can work on these cars, based on the information we have found on the Vehicle Analysis Logs
And also show us the elusive particulate warning light working on the dashboard as it should.
Dave
Cyclemotor1958
We just need to push on with this.
Its unacceptable that these Porsche drivers are being told by the dealers that they cannot do half hour journeys in these cars.
We are still waiting for a response from Porsche Technical to show use how the GPF regeneration can work on these cars, based on the information we have found on the Vehicle Analysis Logs
And also show us the elusive particulate warning light working on the dashboard as it should.
Dave
Cyclemotor1958
Hi Dave
I echo John's words, I can't thank you enough for the help and support you have given me.
We need to get to the bottom of this issue and I truly believe with your technical knowledge and experience you will sort it out.
I urge any other owners who are having or think they may be having issues with GPF or AOS to get in touch with Dave, he really knows his stuff and I'm sure he will help out as much as he can.
Regards,
Mark
Dave
I'd be interested to see if mileage/use has a contributing factor ie only lightly used and/or for short journeys resulting in the GPF not reaching the temps required for regen. Also, as you probably know, Porsche have changed the grade of oil for the 2.0, 2.5 and 4.0 since 2020 from A40 to C40 and GT cars are now required to use GT specific oil. Just wondering if the change is Porsche realising that the grade of oil is a contributing factor to GPFs becoming blocked and possible issues with the AOS.
Dan
I'd be interested to see if mileage/use has a contributing factor ie only lightly used and/or for short journeys resulting in the GPF not reaching the temps required for regen. Also, as you probably know, Porsche have changed the grade of oil for the 2.0, 2.5 and 4.0 since 2020 from A40 to C40 and GT cars are now required to use GT specific oil. Just wondering if the change is Porsche realising that the grade of oil is a contributing factor to GPFs becoming blocked and possible issues with the AOS.
Dan
Hi Guys
Just thought I would send you this YouTube video, it came out years ago, and shows how easy it is to check your AOS.
Regards
David
Cyclemotor1958
Just thought I would send you this YouTube video, it came out years ago, and shows how easy it is to check your AOS.
Regards
David
Cyclemotor1958
Thanks Dave … I’ve seen a video with similar content elsewhere.
LN Engineering have a useful article on the AOS, although I suspect that it was written a while ago since it doesn’t cover the turbocharged 991, 992 and 718-series cars:
lnengineering.com
As you’ve already noted in an earlier post, they cite typical crankcase vacuum readings for 9x6, 9x7 and 9x1 Porsches as:
9x6 & 9x7.1: -4” to -6” H2O, rising to -10” to -15” or even -40” with AOS failure.
9x7.2 & 9x1: -14” to -16” H2O, rising to -20” to -25” or even -30” to -40” with AOS failure.
Presumably the higher crankcase vacuums associated with the DFI engines is to counteract increased blow-by due to higher combustion pressures? You would expect even combustion higher pressures from the 718 turbocharged engines and therefore even higher crankcase vacuums, meaning that the AOS is working even harder!
Note that the 718’s 2.0L engine runs at a higher boost pressure than that of the 2.5 engine, so I wonder if that has some bearing upon why it seems that GPF failure is happening only on the smaller engine?
Jeff
LN Engineering have a useful article on the AOS, although I suspect that it was written a while ago since it doesn’t cover the turbocharged 991, 992 and 718-series cars:
Porsche Air Oil Separator (AOS) for Porsche Boxster, Cayman, and 911 Models
The air oil separator, or AOS, is a critical part of your Porsche’s engine and should be replaced as part of regular maintenance to prevent failures.
lnengineering.com
As you’ve already noted in an earlier post, they cite typical crankcase vacuum readings for 9x6, 9x7 and 9x1 Porsches as:
9x6 & 9x7.1: -4” to -6” H2O, rising to -10” to -15” or even -40” with AOS failure.
9x7.2 & 9x1: -14” to -16” H2O, rising to -20” to -25” or even -30” to -40” with AOS failure.
Presumably the higher crankcase vacuums associated with the DFI engines is to counteract increased blow-by due to higher combustion pressures? You would expect even combustion higher pressures from the 718 turbocharged engines and therefore even higher crankcase vacuums, meaning that the AOS is working even harder!
Note that the 718’s 2.0L engine runs at a higher boost pressure than that of the 2.5 engine, so I wonder if that has some bearing upon why it seems that GPF failure is happening only on the smaller engine?
Jeff
Hi Jeff
When I started out working at a local Porsche independent garage 7 years ago, I saw lots of oil separator failures, with the usual white smoke emissions.
I looked for other ways to test these AOS parts, and found the guys at LN Engineering, had such a tool, they kindly sent me information on how to test the AOS with a manometer.
This information gave me specific values on testing and going forward found lots of faulty AOS before they failed badly.
The guys at LN Engineering are brilliant and if you look at what they are doing to improve the Porsche Cars, you would be amazed.
They posted this AOS information out a few months ago on YouTube and it's seems very relevant now.
Regards
Dave
Cyclemotor1958
When I started out working at a local Porsche independent garage 7 years ago, I saw lots of oil separator failures, with the usual white smoke emissions.
I looked for other ways to test these AOS parts, and found the guys at LN Engineering, had such a tool, they kindly sent me information on how to test the AOS with a manometer.
This information gave me specific values on testing and going forward found lots of faulty AOS before they failed badly.
The guys at LN Engineering are brilliant and if you look at what they are doing to improve the Porsche Cars, you would be amazed.
They posted this AOS information out a few months ago on YouTube and it's seems very relevant now.
Regards
Dave
Cyclemotor1958
Sorry Jeff
For duplicating the LN Engineering video, senior moment, just retired 3 months ago.
Currently working on a 718 Cayman 2.5 with a faulty GPF, will keep you informed as we go along
Kind Regards
Dave
Cyclemotor1958
For duplicating the LN Engineering video, senior moment, just retired 3 months ago.
Currently working on a 718 Cayman 2.5 with a faulty GPF, will keep you informed as we go along
Kind Regards
Dave
Cyclemotor1958
No problem Dave … tell me about senior moments!
Agree that LN Engineering do some excellent work, and the video is very useful for understanding some contributory factors which can lead to AOS failures.
Interesting to hear that the 2.5L engine isn’t immune to GPF failure and I look forward to hearing more updates from you.
Jeff
Agree that LN Engineering do some excellent work, and the video is very useful for understanding some contributory factors which can lead to AOS failures.
Interesting to hear that the 2.5L engine isn’t immune to GPF failure and I look forward to hearing more updates from you.
Jeff
Thanks Jeff
Iam sure we will be speaking soon
Dave
Iam sure we will be speaking soon
Dave
Posts made and opinions expressed are those of the individual forum members
Use of the Forum is subject to the Terms and Conditions
