C204 P244A7A & P244A00 codes

[Trollepoten]

So a family member took her C204 2.2CDI to a shop because she had a check engine light.
They replaced 2 sensors, I'm assuming they replaced the DPF sensors. But the car still throws codes:

P244A7A State : Historic
The pressure differential in the diesel particulate filter (Cylinder bank 1) Is too low. Leakage or a Defective seal was detected.

P244A00 State : Historic
The pressure differential in the diesel particulate filter (Cylinder bank 1) Is too low.

DPF fill level is at 101% which seems to be good. But it doesnt read ash or soot content.
The DPF Pressure sensor reads 0 bar. And doesnt really change when I give it some throttle. Not even when i check the wave.
I dont think thats normal?

My guess would be to check the pipes for blockages going to the DPF sensor?

 

[alexanderfoti]

Pipes to/from sensor probably blocked. They should be replaced at the same time.

Wiring faults at the sensor are also common and should be checked.

 

[mioba]

They are historic codes - delete them

 

[Trollepoten]

Well, finally found the time to check it out. First i deleted the codes and they didnt come back. After 2 days they are back. I was getting a reading from the sensor. But I'll buy a pressure tester to see if the sensor is reading correctly

 

[Trollepoten]

Tested the sensor. Sensor seems to work perfectly. Only thing i can assume now is that the DPF itself is cracked and needs to be replaced. What do yall think?

 

[alexanderfoti]

Have you checked the pipes

 

[Trollepoten]

Yes, pipes dont have cracks in them, and are not leaking either

 

[alexanderfoti]

There can't be 0 pressure with a functional dpf, and if the sensor reads 0 then either the pipes are blocked (with soot usually) or the sensor is bad (but you have tested).

 

[Trollepoten]

There can't be 0 pressure with a functional dpf, and if the sensor reads 0 then either the pipes are blocked (with soot usually) or the sensor is bad (but you have tested).

Yeah so the only thing possible is a bad DPF right? But the crazy thing is that it passed emissions in Belgium

 

[alexanderfoti]

How have you tested sensor

 

[Trollepoten]

How have you tested sensor

I put a vacuum tester on the left tube of the sensor, put 0.5bar on it, and my scanner reads 0.5 bar

 

[alexanderfoti]

And if you rev the engine there is 0 change in the reading?

 

[Trollepoten]

There is a little when revving high, sometimes it would go to 0.1 bar

 

[alexanderfoti]

Then it's working.

You need to erase adaptions for the differential pressure sensor then re teach the fill level for the DPF.

 

[Trollepoten]

Then it's working.

You need to erase adaptions for the differential pressure sensor then re teach the fill level for the DPF.

It is working but it says the pressure is to low, so i would assume no pressure can be build up since the dpf is cracked?

 

[alexanderfoti]

No it's learned a wrong value.

You don't want pressure in your dpf.

0 pressure = dpf missing
A low pressure reading = dpf working and not blocked
A high pressure = dpf blocked.

 

[Trollepoten]

No it's learned a wrong value.

You don't want pressure in your dpf.

0 pressure = dpf missing
A low pressure reading = dpf working and not blocked
A high pressure = dpf blocked.

Wouldnt the sensor relearn itself? I have a icarsoft cr pro+ and there is no option to calibrate the sensor

 

[alexanderfoti]

No, the ecu stores the calibration and adaptions.

 

[Trollepoten]

No, the ecu stores the calibration and adaptions.

I checked and found the option to relearn the dpf. I did so but the check engine light is back on unfortunatly

 

[alexanderfoti]

You need to erase adaptions for the differential pressure sensor then re teach the fill level for the DPF.