Hi Guys & Girls
Without prejudice
Some more information regarding what seems to be happening after Dealers have fitted a new GPF filter on 2 of our cars.
We have two examples of vehicles that had GPF filters fitted by the dealers and after the filter was replaced the oil / ash level, instead of being zero, was unfortunately not the case.
Our first 2 cases, happen to be the first cars that we managed to convince the dealers and Porsche, that this fault on these cars was clearly a manufacturing defect and we would not be paying either a contribution, or the full cost of repairs.
We managed to reverse their decision to charge us, using technical information we collected after looking at the Val GPF reports on each car.
The information on the Val GPF report page 42, clearly showed that these 4 measurements in the reports were showing odd data.
Soot load, calculated and measured values showed odd, and very low readings.
Oil / ash load measured 100% was suggesting the GPF must be blocked, yet these cars drove perfectly well with no performance issues reported.
The exhaust gas temperature upstream of GPF filter was unusually low, compared with the exhaust in filter temperature. These temperatures are calculated, suspect the algorithm providing this information could be wrong, if this car uses an algorithm.
The differential pressure sensor readings seem to be far too low, bearing in mind the dealers are suggesting the GPF is blocked with Ash. Usually you would see higher pressure readings on a blocked filter.
The dealers agreed that after the filters were fitted, the cars could come back to have the oil / ash % level checked. We needed this information to give us confidence that their diagnosis to fit this very expensive part was correct. Bearing in mind that a GPF filter should last a long time, and these cars had very low mileages.
The first car went back into the dealer after 1000 miles covered with the new GPF fitted, and unfortunately the Val GPF report showed an oil / ash value of 38.04 %. The driver of the car had driven the vehicle with many deceleration runs to help keep the filter clear.
We requested to see his GPF condition report after the filter was replaced, before the vehicle left the garage, but unfortunately we had wait a long time to get it.
Thankfully we now have that report, details as follows, I have written this information as it was sent to us.
Requires new GPF filter GPF Filter Replaced
Soot load calculated 0.00 % 0.00 %
Soot load measured 0.00 % 27.45 %
Oil ash load measured 100 % 0.00 %
Exhaust gas temp in filter calculated 368.35 degrees C 414.98 degrees C
Exhaust gas temp upstream calculated 121.48 degrees C 25.60 degrees C
Differential pressure value 2.65 hPa 2.65 hPa
I have highlighted the areas of concern, questions to Porsche Technical
1. Why is the soot load value on the new filter so high 27.45 %
2. Why again are we seeing such a low upstream gas temperature of 25.60 degrees C, which is lower than the faulty GPF temperature we removed. Bearing in mind this is upstream, which is nearer to the exhaust manifold. But as we know, this is a calculated measurement.
3. Why is the differential pressure sensor value the same
Just something else I found while checking through the only customer Val Log I have on another vehicle.
This vehicle requires a new filter, and it’s been authorised to be fitted, these Val logs have 218 pages, on page 42 it shows us the GPF exhaust temperature info.
GPF in filter calculated temperature 316.16 degrees C
GPF upstream calculated temperature 39.79 degrees C
After going through all the pages, I found on page 72, these Catalytic convertor temperatures.
Exhaust catalytic convertor temperature 408.41 degrees C
Exhaust temperature downstream of catalytic convertor 408.41 degrees C
Question to Porsche Technical
If you look at this data on our calculated GPF temperatures, against the actual Catalytic convertor temperatures on this exhaust system it makes no sense at all.
Bearing in mind the GPF and the Catalytic convertor are joined together, one part.
You would expect that the exhaust temperatures in a GPF would need to be correct in order for the ECU to monitor and control the regenerations required if the driving style is not suitable for normal regenerations.
Seems to me that the actual Catalytic convertor exhaust temperatures could be used instead of our calculated temperatures in the algorithm, if the car has one.
We only need around 600 degrees to burn the soot off, and we only seem to get high exhaust in filter temperatures, after we have done a regeneration on the GPF, with the car stood still.
The second car was a real battle, this car was purchased from a Porsche Dealer and when the GPF fault was identified the customer was blamed for putting in the wrong engine oil.
We requested from the dealer the service history on his car and found on the service carried out before he purchased it, the wrong engine oil was fitted by another Porsche dealer.
The Dealer still insisted that the customer had to pay for the filter
We then requested the pre-sale Val GPF report from the supplying dealer, which took weeks to come, when it came it didn’t look like the usual Val GPF report. It was a spread sheet made up with figures.
We insisted they send us the correct Val GPF report, and when it finally came it showed the car went out with a oil / ash reading of 89%. The level 4 soot loading warning light should have been on the dash.
The new GPF was ordered, and fitted, when the customer finally picked up his car, he noticed that the fuel gauge was nearly empty, he had just put in £80.00 of fuel before he dropped it off.
He asked the service adviser where had all his fuel gone, the reply was, we needed to do some regenerations and lots of road tests after fitting the new filter.
The car went back in after 1300 miles, for the oil / ash level to be checked has agreed, but when the customer asked for the Val GPF report, he met with some resistance, he wouldn’t leave the service department till he got a copy of his report.
To his amazement the oil / ash measured value was at 62.75 %. The exhaust gas upstream temperature was 17.35 degrees C, and the in filter temperature was 199.79 degrees C.
He questioned the oil / ash level %, and was told by the reception chap that this figure can go up and down. He left the service department very unhappy, and disappointed.
Sadly the customer sold his car, because to him it was clear that the car wasn’t fixed.
Our third customers car is in the garage at the moment having its GPF filter replaced, and we are waiting for the GPF Val report, to see if the ash load and exhaust temperature figures are correct.
We have quite a few cars at the moment being monitored with an oil / ash level around 85%, driving perfectly well, no light on. We are using diagnostic testers that can give us the same information as what we see on the Porsche diagnostic Report.
On Wednesday I had a call from one of our members with a GPF issue that’s being looked by a Porsche dealer at the moment. This car has been in the workshop several times for this fault and they have kindly let us see the GPF information on the car. Has a result of my involvement and the dealers help we found a faulty differential pressure sensor which was affecting the upstream exhaust temperature reading.
Before the sensor was replaced the temperature reading was 21.35 degrees C, after the sensor was replaced it was 352.10 degrees C, an increase of 330.75 degrees.
The old sensor was showing a pressure reading of 2.65 hPa, and the new sensors reading was 4.23 hPa. The old sensor didn’t flag an engine warning light, so it was under the radar.
What's funny is we have seen this 2.65 hPa differential pressure sensor reading before, see above.
After looking at an earlier Val GPF report on this car we found the same pressure reading of 2.65 hPa,
Brilliant information, proving a clear link between the differential pressure sensor and the exhaust upstream temperature.
The reason for the call was to tell me, that the dealer told our member that a memo was sent out to all Porsche Dealers to not send out any information, including Val reports, and any printed information etc.
So thankfully over the last 10 months we have gathered enough information to prove that the GPF control of our cars is not correct.
The absence of the particulate filter warning light on the dashboard on all the cars we have investigated is proof that this system is not working correctly on these cars.
You may remember I sent out a reward of £100.00 to anybody that drives one of these 2019 cars, that can send us a photo of the particulate warning light coming on, still waiting.
We are now at a stage in this investigation on these cars, that even when a new filter is fitted it hasn’t fixed the fault, and the first 2 cars mentioned above were sent out not fixed correctly.
The GPF Val reports on both these cars clearly showed ash and temperature reading issues.
We must remember that any diagnostic information on your car is your property and you should be intitled to have a look at it at any time.
We have put in a lot of time and effort in looking into the diagnostic data and what’s happening to these cars, because Porsche and the dealers have said it’s the customer that’s caused the failure of these GPF filters, wrong engine oil, and driving style, and they cant be used on half hour journeys.
We will push on
Dave
