Cayman 718 GPF Failure

[Cyclemotor1958]

Hi Guys& Girls

Without prejudice

Following on from my last post regarding exhaust back pressure on our GPF filters.

Found this on YouTube, it shows you the function of the differential pressure sensor and how important this sensor and its readings are to the emission device on our cars.

See link below.

I know I go on about checking for back pressure when these cars are reporting the 100% oil ash load, and the need to change the filter.

But if the differential pressure sensor information is correct, and reading are very low, then we have the answer.

Normally if a filter is starting to get quite blocked, you would see a reading at tickover between say 10 to 100 HPA.

If you increase the revs to between 2.5 and 3K you may see 250 to 300 HPA.

In the last 2 days I have seen sensor readings no higher than 4.0 HPA convert this to PSI and you get 0.058 PSI.

I have said many times that the data we are seeing on these GPF filter reports page 42, make no sense at all.

Yet the dealers and Porsche seem to be ignoring the wrong information that's recorded on their report, and it's been the same on all the GPF reports I have seen over the last year.

Let's use the information we have and start looking at the real issue.

We have Cars that had filters fitted last year, that already have high oil ash % figures recorded and they will be going back into the dealers for them to have another look at this problem.

We could save Porsche alot of money if we check the actual back pressure before the exhaust are removed.

Sorry to go on again

Dave

 

[Paul-718gts]

Well as you know Dave my car is back in next week for further investigation work following its first VAL check that showed a reading of 27% Ash after 500 miles of driving with a new filter being fitted under warranty along with a new sensor.

I believe at the time my car may have been the only one that had both parts fitted at the same time ?

I must say the Principal at the dealership has been very supportive, along with his team of Gold techs.

With the additional tests and questions that we have requested hopefully this will help find the root cause we are all seeking.

Let’s hope we can use this as an opportunity to finally find a solution to this ongoing issue.

 

[Cyclemotor1958]

Morning Paul,
Looking forward to getting some positive results and explanations, fingers crossed.
Have a good weekend, catchup soon
Dave

 

[Cyclemotor1958]

Hi Guys & Girls

Without prejudice

Two more 718 drivers contacted me over the weekend with GPF issues asking for advice.

Both had the usual oil ash loading at 100%, and the GPF needs replacing.

Usually when your filter gets to 100% and the warning light comes on, you will be told the GPF needs replacing because its blocked with ash.

What you are not told is that something doesn't seem right with the differential pressure sensor reading that monitors the pressure in your GPF.

It looks very very low.

Well, it could be a faulty sensor.

Let's manually check the pressure in the GPF which will confirm the sensor reading is accurate.

Good idea, worth a look

A differential pressure sensor reading of 6.25 hPa was sent to me last week on a GPF filter that was showing the usual 100 % oil ash loading.

If you convert 6.25 hPa to PSI you get 0.09 PSI.

So no pressure at all

Why are we not looking at this in more detail.

It's been the same on all the cars I have been involved with, that required new filters, and its continuing to be the same on these cars going forward into this year.

Just a thought

Kind Regards

Dave

 

[JohnCRS]

A (non) update. So far the club has not been able to get any answers from Porsche GB or Gmbh on this issue. We are now focussing on simply trying to get a technical representative to read this thread, or at least the later pages, and to comment on what is going on. If we can achieve that we have somethiing to work from.

 

[Paul-718gts]

A (non) update. So far the club has not been able to get any answers from Porsche GB or Gmbh on this issue. We are now focussing on simply trying to get a technical representative to read this thread, or at least the later pages, and to comment on what is going on. If we can achieve that we have somethiing to work from.

Hi John,
Disappointing to say the least that the owners club sounds like it has no leverage with the Brand given the number of loyal supports that are members.
As we haven’t seen anything in the monthly mag for a few editions apart from a very small paragraph, why don’t we look at a double page spread in next months, I am sure David is more than capable of writing a very factual article that would grab the attention of the brand if that is what the club are trying to achieve?
You could even ask for some of those effected by this situation to add their journey so far to give David’s article some real world credibility.

More than happy to donate my copy to a local dealership service area for customers to read that maybe are not enthusiasts and purely buy based on the brand recognition/kudos created by us the brand sponsor’s..

Surely it’s got to be better for the club to go to press with an article on this matter rather than another non brand mag ?

My understanding is that this post is up to over 30k views… must be the biggest story in years.

 

[Scrounger]

I’ve said this more than once and I’ll say it again. Go to the motoring press.

It’s all well and good saying this is happening and this is wrong but if you go down the supposedly official route and get no response the only other option is to highlight it to the masses. They’ll have no option but to take notice and respond as it’s potentially damaging to the brand and to the users pocket if it continues.

It just needs someone to talk to the likes of Auto Express to start the ball rolling.

Dan.

 

[Cyclemotor1958]

Hi Guys & Girls

Without prejudice

Following on from my last post and our focus on the technical GPF details on these cars, found this information regarding our oil ash issue.

What makes this information interesting is the mention of the oil ash load as a calculated reading.

We have never seen in the calculated reading K230 any recorded information at all.

Its always been recorded in the K231 section of the report, and when it gets to 100%, the light comes on and we have a problem.

This information is from the Porsche PIWIS coding information, found in the ENGINE OVER REV REPORT, ATTACHMENTS.

It clearly shows the Particle filter calculated oil ash load.
With an instruction to select values F12.
It also mentions the soot load.

This is very interesting and we need to look into this in more detail.

We currently have a vehicle in with a Porsche Dealer at the moment and we will be suggesting they check this out.

Enclose a GPF report showing the oil ash readings in detail, and the coding information I found.

Looking forward to next weeks investigations.
Dave

 

[Cyclemotor1958]

Hi Guys & Girls

Had a chap contact me from the 718 forum concerning the GPF report I sent out regarding the oil ash reading.
This is my reply

Without prejudice

The GPF report I sent you shows a 100% oil ash reading, remember this reading doesn't mean the GPF is blocked, infact all the ones we have checked the back pressure on, had no real pressure at all.

Given the average mileage these vehicles have covered it's what you would normally see, a simple check to see if your filter is dealing with the soot is to check your rear exhaust tips.
You should find a light grey deposit with a slight brown tint, which is the burnt ash, no soot.

If you look at my previous post, and the information I found concerning the oil ash reference as a calculation in the coding section of the over rev section on the PIWIS tester, this is something to investigate.

I would expect any instruction from the ECU that puts a warning light on the dashboard, to come from a calculated value, not a measured value, as you can see on the GPF report.
It seems to me it's the wrong way round, a measured value can increase and decrease.

The main problem is we can not rely on this information from the GPF report as its based on an algorithm that is incorrect and the only actual reading it giving is the differential pressure current sensor reading.

All the rest are either measured or calculated, and sometimes we find 0.00 readings are found were you wouldn't expect them to be.

Yet when a GPF filter is condemned, the differential pressure sensor reading is not looked at and acted on.

We will get to the bottom of this, with or without Porsche Technicals help, it's a shame we could not work together, after all it's their problem, and their customers who are suffering and losing patience with them and the brand.

Bye for now

Dave

 

[Cyclemotor1958]

Hi Guys & Girls

Without prejudice

Just found this on YouTube, this is what we need, re setting a DPF filters values.

Regards
Dave

 

[Cyclemotor1958]

Morning Guys & Girls

Without prejudice

Sorry it's me again, another Cayman driver contacted
me yesterday with the usual P242F oil ash load DTC.

I have put together this short diagnostic check below,
to check for back pressure and possible differential pressure sensor faults.

You need a manometer set to hPa to measure this pressure reading, it can be purchased on Amazon for around £50 to £60.

This same manometer can be used to check your AOS vacuum readings, you just need to buy a oil filler cap, to connect the two.
The readings for the AOS are measured in inH20,(inches of water).

My test info.

Look at the GPF report page 42 of the Vehicle Analysis Log

Check the oil ash measured K231 value, it's usually at 100% if the engine light and warning message is on the dashboard.

Check both soot load values, K221 & K230, they usually have either no values or just very low soot load values.

Check K251 differential pressure sensor current value, if low, which it usually is, carry out these checks below.

Go to the differential pressure sensor and remove both rubber pipes, make sure these are not blocked with soot.

If OK, you then start up the engine, connect a manometer to the larger supply pipe and check the actual exhaust back pressure in hPa, from the GPF.

You then compare the manual and diagnostic readings from your diagnostic tester with the car running.

This then confirms the sensor is either working correctly or not.

If all is OK, and no significant back pressure is seen, then this proves that the GPF filter is not blocked with ash.

This also confirms that the filter is not blocked with soot.

I have sent this information out to 5 owners this morning in a hope that we can get some valuable information back to backup our suspicions that these GPF filters are not faulty.

Will keep you informed

Regards
Dave

 

[Jonathankrum]

Hi Dave,

I am grateful for all your posts on this matter.

Unfortunately the same thing has happened to my wife's 2019 Boxster 718 2.0. The car is currently at an OPC where it has resided for the last two months while they decide how much of the £8,500 bill I have to pay! They have referred the case to Porsche UK and it is an ongoing, not yet resolved situation.

Any help and advice would be gratefully received! thank you again J

 

[Wrightrubber]

Hi Jonathan
Sorry to hear of your situation, I started this post back in May 2023 when I had the same problem and the OPC wanted to charge me £7500. Dave then got involved and with his help and technical knowledge it was replaced free of charge. I have spoken to Dave today and mentioned your post, he has asked if you can give him a call tomorrow (Friday) on 07769 590119 and he will see what he can do to help.
Regards
Mark

 

[Jonathankrum]

Hi Mark,

Thank you that’s kind of you and Dave, will do, it is much appreciated. This whole situation is so ridiculous for such a great brand to be dragging its heels like this! Best wishes Jonathan

 

[Cyclemotor1958]

Hi Jonathan,

Just got in,

Please ring me tomorrow, morning would be good, and we will get this sorted out.
I have just picked up a message from one of our 718 owners, we have managed to get another GPF filter condemned by a Dealer authorised.

So thanks again to the dealer and Porsche GB

Let's push on

Dave

 

[Paul-718gts]

So as a further update to my journey over the last 8 months,changing these filters is not the answer to this problem.
I like a few others are on their 2nd filter which was replaced under warranty FOC with Dave’s support.
My first VAL check agreed with the dealership after fitting a new GPF showed an ash reading of 27% after 500 miles.. a second check has been conducted after another 300 miles and is now showing a value of 43% ash fill..
At this rate it will end up being full again after less than 2000 miles.
This clearly shows that the root cause to this problem is something else failing which is progressively getting worse which then has a dramatic effect on increasing the fill rate once the initial root cause failure is evident.

What I can also share is that my original filter increased from 73% to 100% within 1300 miles..

Whatever has gone wrong originally is clearly not fixed.

Further investigations are continuing in co-operation with the dealership.. and support from Dave.

One word of advice for anyone that is having their filter changed, you need to insist on having at least 2 VAL checks completed after fitting after an agreed mileage or time period.

 

[Cyclemotor1958]

Hi Guys & Girls

Without Prejudice

You will need a comfy chair and a few cups of tea for this post

Well it's been a busy week, currently working on 4 new cars with our GPF problem.

The dealers are still telling our drivers that they need a new GPF filter due to it being blocked with ASH 100%.

With the usual cost to repair in the region of £8,000.

We now have sufficient evidence to prove these filters are not blocked, we have a number of our cars that had a new GPF filter fitted last year going back to the dealers with high oil ash readings already.

I have given our drivers information on how to check for back pressure on the GPF filters to be forwarded on to the
dealers to confirm there is some.

Its's not working, nobody is listening, we have no dealer generated information back to us showing any back pressure readings, WHY NOT.

It's unbelievable that the back pressure is not checked, if it was, they certainly would not be replacing the expensive GPF.

So basically the dealers are not diagnosing the fault on these cars correctly and they should be.

They are quite happy to upset their loyal customers with a large repair invoice, using the excuse that the wrong engine oil or driving style has put them in this position.

The trouble is these GPF filters are not blocked with ASH, so why are they doing this.

Last year we had a car in with a Dealer who had confirmed it required a new GPF, cost £8,500.

They were told by the technical department at Reading to check for any signs of oil contamination that could possibly increase the ash levels in the GPF.

These checks included, removing the spark plugs, checking for cylinder leakage past valves and piston rings and checks on the turbo.

The dealer presented an invoice to the customer of around £900.00 for the work carried out.

At this point the faulty GPF had not been authorised, we challenged this extra diagnostic work has being unnecessary, and eventually after sending in our objections they agreed to waver the invoice and cover the GPF 100%.

If you go back to page 5 on the Porsche Forum, subject Cayman 718 GPF issues, you will see my first post about AOS failure and the possibility of it failing and causing oil contamination that would end up filling the filter with ash.

Has we have said before 90% of the ash formed is from burning engine oil.

We didn't know at the time that these cars didn't have any back pressure to support blocked filter, WE DO NOW.

Our dealers are ignoring the low differential pressure sensor readings seen on page 42, and not even checking and confirming the reading is correct.

Because if it is correct, they would not be removing the GPF.

When you look at the information on the GPF report all you see is either calculated or measured readings, the only sensor on the GPF that shows an actual reading is the differential pressure sensor.

All the other readings are part of an algorithm that runs this GPF, even the Catalytic Convertor temperatures are not live sensor readings.

The one sensor that's missing on our GPF filters is an exhaust temperature sensor which gives the ECU actual live temperature readings.

It's funny that these temperature sensors are fitted to our 718 GT4 cars that don't have our problem.

My theory is that oil contamination from the AOS is affecting the signals back to the ECU, from the oxygen and air mass sensors, that may affect the algorithm calculation and measured values we are seeing.

Remember the vacuum readings on these AOS devices have not to be checked on these cars. We have checked a few ourselves and found very high readings around 35 to 45 inches of water, which is the measured value.

On a generation 2 911 the vacuum readings should be between 14 to 16 inches of water measured.

The last car I had checked at a well known Porsche independent was so high it showed an error code, because it was so high it was out of the testers range. The manometers range was up to 55 inches of water measured.

I actually paid for this manometer and sent it to the Porsche independent so I could get the data.

We have had conversations with many dealers that said they did not have a manometer to check them.

And to make matters worse they are not allowed to use a tool that's not Porsche approved.

The only way you can check if the AOS vacuum is within specification is with a £50.00 manometer and a Porsche oil filler cap.

These AOS devices have been superseded since these cars where built, could this be a clue.

So why isn't a GPF back pressure and a AOS vacuum check being carried out by the dealers and why are Porsche Reading not asking for this vital information.

From now on if I have any more contacts from owners of these cars with the GPF oil ash issue, we will be asking for this information to be provided as a minimum, along with the GPF report page 42 showing current readings.

Sorry to go on but this issue is not going away, I've just had a car that had a new GPF fitted last year by a dealer, it's oil ash light came on again shortly after the repair.

It went back to the dealer lots of times, couldn't be resolved.

The owner finally had enough and sold it to We buy any car, they then passed it on to an auction company.

The car was sold again and the GPF light came on again 100 miles from the new owner picking up his new car, usual P242F oil ash load exceeded.

David

 

[Cyclemotor1958]

Hi Guys & Girls

Without prejudice

Following on from my last post and my frustration with some of our dealers that are currently trying to convince our drivers that they should pay for a GPF they don't need.

They are still using the reason for failure as the short journey times found on their Val reports.

If the car is out of the dealer network they try and find that the wrong engine oil was used, so no help.

Neither of the above will block a GPF filter with ash over the low mileages we have seen on these cars.

Especially if the soot regeneration system is working as it should do, and the regeneration particulate filter warning message can be seen coming on the dashboard.
Instructing you to see the drivers manual, and carry out a deacceleration road journey to clear the message.

These cars are now atleast 5 years old, and to date we have not seen this regeneration message on any of our faulty cars.

If you remember last year I offered a reward to anyone who could send me a picture of the said warning message.

We'll, no photo, why is this, afterall this should be working on a vehicle that is fitted with an emission system that should look after itself, but occasionally require the drivers help.

Help is when we do short journeys, and journeys in colder months.

Well, I have a photo of the actual warning message, will let you see at the bottom of this post.

When this light comes on it can leave a DTC code P2463,(particulate filter soot load high).

When this code was checked we had in K211 soot load calculated 38.10 % and in measured K221 43.75 %.

We have never seen such high soot values in any of the cars we have dealt with todate.

More often than not we don't see any soot values at all.

I have just seen today a vehicle with 100% oil ash recorded, with zero soot recorded, and the usual very low differential pressure sensor reading.

The thing I don't understand is that if these filters are blocked with ash to 100%, why isn't the differential pressure sensor seeing a high backpressure and showing this on our reports.

These sensors can not distinguish between soot and ash combined, this sensor should look after the soot, like on every diesel car on the road.

The Ash reading comes from a measured value, measured from where ?.

Just a thought, if we removed the soot loading warning regeneration light function from every diesel car on the road tonight, the whole country would come to a grinding halt.

So why is it that the dealers are ignoring this function on the cars, not looking at the GPF detail page 42, not even checking for exhaust back pressure, and finally not checking the vacuum on the AOS that's been superseded since these cars where built.

They would rather upset their customers, not ring them back when asked, spend weeks on these cars, after new filters have been fitted, and generally contribute to an awfully situation, that most of these owners will never forget.

It's time somebody at Porsche got a grip of this.

Regards
Dave.

 

[911hillclimber]

The frustration is clear, the arguments are too, but the Company is not interested, just need to make new cars for the queues of people wanting a Porsche.

I for one cannot see Porsche as a leading car manufacturer, and will never buy one.
My Boxster 987.2 has been a real pain at times and it is a very simple car compared to these cars with these issues.

Quality design seems to have gone when the cars are used, and weakness shows.

This Club cannot get to Porsche GB or Germany.

Only resource left is to publically shame, but I think even that will be ignored. How about the SMMT?

The attitude seems to be thoughout the Company from design to sales and service.

Good luck cracking it, I hope your perseverance will pay off.

 

[Scrounger]

Dave

Firstly I thank you for all your efforts. Sterling work however, it now appears you’ve hit a wall when asking the same questions. We are all pretty much convinced there is an issue with either the sensors or software on these cars but no one is listening. With that in mind I really do think it’s time to take it to the press so Porsche will sit up and listen. I’ve felt with Auto Express before and their researches are very keen for a story.

I wouldn’t be too concerned about rocking the boat.

Dan.