P2463 won't reset after DPF clean

[Charliemonkey]

Hi,
2014 Leon ST FR 2.0 TDi 184 CUPA diesel. 195000 miles
Had P2463 (DPF soot accumulation fault code), car goes into reduced power mode after about 25 miles but this clears each time with ignition cycle. I took the DPF off (a right pain of a job) and had it cleaned - pressure drop was 60mBar now its 20mBar so the clean was effective.
Refitted the DPF but can't clear the fault code with a Snap-On Zeus tool. The tool has the specific option to reset the DPF after being changed but that doesn't run and the P2463 fault code wont clear.
There are no other engine fault codes.
Have checked the DPF pressure sensor feedback at the connector ansd also with an Autel scanner on live data and that is good - reading just over 1V and 10hPa at idle and a bit higher at 2500 rpm (no load). oddly the Zeus reads 0hPa for the DPF pressure drop - Snap-On technician connected remotely and couldn't get the code to clear, couldn't reset the DPF and didn't know why the Zeus wouldn't read the pressure either.

Anyone got any ideas what may be the issue please?

Thanks in advance, Nick

 

[SuperV8]

P2463 is also often associated with your pressure sensor.

Pin number	Wire code or colour	Component	Pin number	Wire code or colour
1	Yellow/Grey	E1 Engine control unit	A 13	Yellow/Grey
2	Brown	E1 Engine control unit	A 37	Brown
3	Yellow/Brown	E1 Engine control unit	A 15	Yellow/Brown

1: check the sensor signal:
Turn the ignition on. Connect a vacuum pump to the connection in front of the diesel particulate filter and apply different pressures. Measure the voltage on pin A 15 - E1 Engine control unit and compare the findings with this chart:

Absolute pressure p(bar)	Voltage U(V)
0	0.8 - 1.2
0.5	2.7 - 3.1
0.7	3.3 - 3.6

Does the voltage match the above specifications?

Yes:
This test has been completed successfully.

No:
Turn the ignition on. Connect a vacuum pump to the connection in front of the diesel particulate filter and apply different pressures. Measure the voltage on pin 3 of the differential pressure sensor. Does this voltage match the above specifications?

No:
Check the supply voltage and ground connection. If both are correct, renew the differential pressure sensor.

2: check the supply voltage:
Turn the ignition on. Measure the voltage on pin 1. Is it between 4.8 and 5.2 V?

Yes:
This test has been completed successfully.

3: check the ground connection:
Turn the ignition on. Measure the voltage on pin 2. Is it between 0 and 0.2 V?

Yes:
This test has been completed successfully.

 

[Charliemonkey]

P2463 is also often associated with your pressure sensor.

Pin number	Wire code or colour	Component	Pin number	Wire code or colour
1	Yellow/Grey	E1 Engine control unit	A 13	Yellow/Grey
2	Brown	E1 Engine control unit	A 37	Brown
3	Yellow/Brown	E1 Engine control unit	A 15	Yellow/Brown

1: check the sensor signal:
Turn the ignition on. Connect a vacuum pump to the connection in front of the diesel particulate filter and apply different pressures. Measure the voltage on pin A 15 - E1 Engine control unit and compare the findings with this chart:

Absolute pressure p(bar)	Voltage U(V)
0	0.8 - 1.2
0.5	2.7 - 3.1
0.7	3.3 - 3.6

Does the voltage match the above specifications?

Yes:
This test has been completed successfully.

No:
Turn the ignition on. Connect a vacuum pump to the connection in front of the diesel particulate filter and apply different pressures. Measure the voltage on pin 3 of the differential pressure sensor. Does this voltage match the above specifications?

No:
Check the supply voltage and ground connection. If both are correct, renew the differential pressure sensor.

2: check the supply voltage:
Turn the ignition on. Measure the voltage on pin 1. Is it between 4.8 and 5.2 V?

Yes:
This test has been completed successfully.

3: check the ground connection:
Turn the ignition on. Measure the voltage on pin 2. Is it between 0 and 0.2 V?

Yes:
This test has been completed successfully.

Hi,
I wondered about the sensor so have checked it as follows:
The feed is 5V
Ground is 0.01V
signal is 5.7V when the connector is OFF the sensor (ECU error check)
signal is 1.0V with engine off (0hPa)
signal was 1.88V at idle and 3.0V at 2500 rpm (no load) with the blocked DPF
signal is now 1.04V at idle and 1.17V at 2500 rpm (no load) with the clean DPF
All voltages measured at the back of the connector.

My Autel read the sensor voltage from the ECU at 1.033V at idle and 1.164V at 2500 rpm (no load) which matches what I measured at the connector.
The Autel read the adapted DPF pressure drop as 10hPa (1.033V). The raw value was 9hPa and the offset was -1hPa.

The ECU detects when the sensor is disconnected and gives a DTC that can be cleared when the sensor is reconnected.

That all seems reasonable to me and seems to indicate that the sensor is working correctly?

The DPF pressure drop (measured off the car when being cleaned) was 60mBar blocked and 20mBar after cleaning (at a slightly higher flow rate).

Appreciate any thoughts please?

 

[SuperV8]

Do you have a mityvac you could plug into the sensor to give it a known pressure drop to measure the voltage?

 

[Charliemonkey]

Hi,

I don't have anything fancy with a calibrated pressure gauge but have a brake bleed pump that has a mechanical gauge on it that will indicate the approximate pressure. I can try that and see what sensor feedback I get.

thanks for your replies, much appreciated.
Nick

 

[Charliemonkey]

Hi,
My pressure sensor has 2 ports but only one has a pressure pipe connected to it, this goes to a port in the transfer passage after the CAT and before the DPF, the other port is open to atmosphere (presumably under the assumption that the pressure after the DPF is only the rest of the exhaust and muffler so close to atmospheric pressure anyway).

Wouldn't the port before the DPF see a positive exhaust pressure relative to atmospheric when the engine is running?

If so, why do I put a vac pump on this port to reduce the pressure below atmospheric to check the sensor is working correctly please? I would expect to need to apply a positive pressure.
Thanks, Nick

 

[SuperV8]

Good point - you could put positive pressure on the inlet side - or vacuum on the outlet (free air side)

In which case - maybe a bike pump or tyre pump with a gauge?

 

[Charliemonkey]

Hi
Have checked the pressure sensor live data against pressure from a pump with a digital pressure readout.
0pressure is 1.002V and adaptive 1HPa
0.4 bar is 2.365V and adaptive 393HPa
0.5 bar is 2.688V and adaptive 486HPa
0.6 bar is 3.05 V and adaptive 585HPa
0.8 bar is 3.87V and adaptive 820HPa

I think the sensor is fine and the ECU is reading it correctly so there must be another reason why the DPF can’t be reset and the code won’t clear.

anyone else had this issue please?
Would VCDS definitely resolve it?

thanks, Nick

 

[SuperV8]

Will it let you calibrate the sensor, like you would do fitting a new sensor?

 

[Charliemonkey]

It seems not.
I used access code 27971 which it seemed to like but when I try to reset the learned value of DPF pressure sensor it says ‘test not supported or conditions not met’ request out of range (0x31).
I get the same response when trying to reset the learned values of the DPF.

it did let me carry out adaptation of DPF pressure sensor. That was successful.