ApplagApp Forum

Hello community,

I have been using the application for some time now, and it has allowed me to better understand how the DPF regeneration cycle of my Skoda SUPERB 1.6TDI CAYC (11/2011, 183,000km) works, even if my problem is not not solved:

For about 6 months, my DPF light has been coming on regularly even though the problem had never occurred before. I think this problem appeared because the EGR valve was making a suspicious "clicking" noise.

By unplugging the power plug from the EGR valve, the noise disappears. This seems to indicate that the EGR valve is stuck, and this is confirmed by the app (valve always 100% closed, regardless of RPM and engine speed).

On the other hand, I also note that the differential pressure is often very low and varies very little: from 0 hPa to around 10 hPa on average and exceptionally 15 hPa during strong acceleration.

Finally, I notice that the DPF goes from 60% filling to 100% in one go, which creates a regeneration cycle approximately every 800 Km. After few minutes, if I don't drive for 15 minutes on the highway at high speed, the DPF light comes on.

My questions are:

– Do you think that blocking the EGR valve in the closed position could cause the recurring problem with the DPF warning light on the dashboard?
- Is it normal that the differential pressure is always so low (I read somewhere that the ideal operating range is between 25 and 30 hPa)?
- Is it normal that PASSIVE particulate filter regeneration at high speeds on motorways does not work? In fact, my FAP never manages to heat above 300-350 degrees, except in the ACTIVE regeneration phase, when post-injection 1+2 is activated by the ECU.

I would like to know what to replace: the EGR valve entirely or simply the differential pressure sensor, or possibly carry out a dismantling/cleaning of the DPF (I have already tried 4 different additives in the fuel to try to clean but it doesn't work : nothing does not change...). Since the appearance of this problem, I have also noticed an excess consumption of around 1L/100km, even if the car remains powerful and dynamic, without any other apparent problem (no any errors in the ECU).

Thank you very much for your comments!

nfranq

There are safety functions in the ECU to prevent the risk of fire in the filter, one of them is the mileage forced regeneration that occurs near 750-800km.
You see the sudden increase of the calculated soot mass because it's the ECU that forces it to 100% to start the regeneration process.

You have to understand if your very lor filling rate of the filter is real or simply the sensors can't give correct information to the ECU.
A first change of the differential pressure is probably the cheapest try you can do. But I suggest also to wait the advise of some expert. I studied the DPF system to make the app, but I'm absolutely not expert in the related issues.

Hello,

After replacing the differential pressure sensor, I inform you that the problem has not been solved. It is probably another faulty sensor in the exhaust line but I do not know which one.

So I simply decided to ignore this warning from the DPF warning light which only occurs when the driving time on the motorway is not enough to bring the soot rate back down below 6.

The warning light finally goes off on the following journeys, and I think I will leave it at that. The car is already a certain age and I do not want to undertake more expensive expenses at this stage.