Dear Superb II owners,

 

I just have a question about "Control system for exhaust" warning lamp

I'm noticed, the "Control system for exhaust" warning lamp did not go out after started the engine.

I'm stopped the engine, and read the manual.

After a quarter hour, I've checked it some cases, after starting the engine it was normal, the warning light hasn't remained on.

What are your experiences, in the most common cases which will be the cause of this behavior?

I don't know why happened this.

 

Thanks in advance.

Until you get the fault codes read it's anyone's guess.

Regeneration?

It sounds like a faulty sensor - but as to which of them it could be - that's just guessing and a finger in the wind. Then again, you may have an issue that is borderline and is going to get worse and leave you stranded or in "limp home" mode at best.

 

Like Tech1e advised - you really do need to get the fault codes read.

Hi All,

 

I was in the local official service technician, who ran a diagnostic on my car.

The fault code is P245400 Diesel Particulate Filter (DPF) Differential Pressure Sensor, Short to GND

It happened two times.

The vehicle environmental and running parameters are when the fault is occurred:

Engine RPM: 900.0 1/min

Normal load value: 16.47%

Vehicle speed: 33km/h

Coolant liquid temp: 90C

Intake air temp: 42C

Intake air pressure: 990mbar

30th point current: 13.8V

Failed learning process based on OBD: 38

DPF before and after pressure diff. pressure sensor default value: -215hPa

DPF pressure difference: -207hPa

DPF difference of pressure difference: 1hPa

DPF dynamic difference of pressure difference: -8hPa

Ambient outside temp: 19.46C

DPF soot mass measured: 10.81g

DPF soot mass calculated: 20.71g

 

My questions are,

a.)  what can be the cause of this failure, short to GND?

b.) what is a normal range (or maximum value) of soot mass calculated or measured value(s)?

 

(I just remark, As I think I gave chance for regeneration, I always pay attention to the cooler fans if it was not stop, when I remove the ignition key. After it, I went to a small trip with min 2000rpm and min 60km/h the distance usually about 40km)

 

1st. Here is the VW Self Study Program Guide which related to the DPF differential pressure sensor.

2nd. Here is another VW SSP Guide about 2.0 Liter TDI Common Rail Engine

 

In the 2nd. listed SSP doc I found the possible answer for my question b.) on page 64:

"If the regeneration drive is not successfully completed and the load condition of the diesel particulate filter has reached 1.41 ounces (40 grams), Diesel Particle Filter Indicator Lamp K231 and Glow Plug Indicator Lamp K29 will light up simultaneously."

 

Thanks in advance.

Edited 27 June, 20169 yr by ujtordai

Short to ground means there is a wiring fault between the pressure sensor and the ECU (or possibly the sensor or ECU themselves).

Requires a wiring check to see where the issue is.

Could be a dead sensor too. They do fail sometimes.

On the mondeo they have pressure differential pipes across the dpf which measure how blocked it is .they occasionally can break/burn through. They may have something similar on the skoda ,worth a quick look at the dpf underneath

On the mondeo they have pressure differential pipes across the dpf which measure how blocked it is .they occasionally can break/burn through. They may have something similar on the skoda ,worth a quick look at the dpf underneath

A damaged pipe wouldn't give a short to ground fault, that's an electrical issue.

Whatever it turns out to be ,a visual inspection can often spot the problem

Hi All,

 

I'm inspected visually, but I don't know why left one tube alone freely?

Here are the photos about that.

Do you have somebody an idea?

 .

Edited 28 June, 20169 yr by ujtordai

That's fine. As all the post DPF sensor tube measures is ambient pressure it doesn't actually need to be connected.

That's fine. As all the post DPF sensor tube measures is ambient pressure it doesn't actually need to be connected.

I thought that this must be connected before and after the DPF.

Tomorrow will be replaced this sensor. (this not cheap in my country ~ GBP 69 plus fees)

Thank you of the replies!

Edited 28 June, 20169 yr by ujtordai

It's connected before yes. But think about it logically. What is a pipe after the DPF connected to? It's connected to atmospheric pressure and that can be picked up anywhere so why bother running another pipe that can get blocked, no point.

Why are you replacing the sensor when you don't know it's the fault? Especially as it's expensive. The fault code is an electrical code, although it could in theory be the sensor this should be proven by diagnosis.

If you do change the sensor the new one will have to be calibrated before you start the vehicle.

Why are you replacing the sensor when you don't know it's the fault? Especially as it's expensive. The fault code is an electrical code, although it could in theory be the sensor this should be proven by diagnosis.

If you do change the sensor the new one will have to be calibrated before you start the vehicle.

Suggested me the service technician, I checked the cables the plastic cover of those are not damaged the cables are stable as I saw.

I read about the calibration, I hope in the service provider it know well.

Fingers crossed for you then, as it's a stab in the dark.