Hi all,

 

I'm having a DPF nightmare at the moment with my 58 plate CR VRS Octavia, any help will be much appreciated.

 

The following occurred:

1.) Coil light came on intermittently, no sign of any problems.

2.) Coil light stayed on, no problems.

3.) Distinct lack of power, probably no turbo.

4.) Take it to a local garage, who replace the turbo actuator.

5.) DPF light, EML and coil light now on.

6.) Garage say DPF needs to be changed or cleaned, as it's too full for regen.

7.) Garage clean DPF, does nothing and still won't regen.

8.) Garage check EGR, no problems found.

9.) Garage take off entire DPF, same problem!

10.) Garage, who have great policy and don't charge me for things that didn't fix the car, don't want to help anymore. They spent 12 man hours altogether on trying to fix it. They recommend going to get diagnostics at a main dealer.

11.) Go to dealer. They tell me I need a new DPF and want to charge me £2200!!!!

 

Now, from the above, I can't see how this is the DPF. To me it seems like a sensor problem, but I'm not sure witch and I'm no expert. Currently, I can't really drive the car and it's essentially a right-off. I've got 160k miles on it, but expected to get it to 250k.

 

Any help will be greatly appreciated.

 

Cheers,

 

L.

Any error codes? If it has stored error codes, it wont do a regen.

As above, you need to get a VCDS scan as a starting point.

 

Probably also worth looking at the DPF measurements to see how much ash or soot the car thinks is in the DPF and if the sensor values look sensible.

 

The longer you wait, the more clogged up the DPF will get and it's more likely to need replacement rather than just a regen.

Will get error codes ASAP and get back to you. Not driving at the moment. 

 

Do you think it strange that it was only once the turbo was fixed that the DPF error was then flagged? Could this be a pressure calibration issue? I'm assuming the DPF sensor uses pressure to measure the soot level, right? 

 

I'm also confused about why there was still an issue when the initial garage took the entire DPF off. Unless they didn't do it correctly and not negate the relevant sensors. I guess you can tell I don't really know what I'm talking about.

 

thanks

 

I'm also confused about why there was still an issue when the initial garage took the entire DPF off. Unless they didn't do it correctly and not negate the relevant sensors. I guess you can tell I don't really know what I'm talking about.

 

 

It doesn't work that easy. Your car knows that there IS a DPF device and if you take it off, it will still think that there is a problem. That's why DPF removal process includes removing it AND programming work.

Thanks Jevpls. Understood. Before garage #1 took the DPF off completely, they also took it off to clean it. They said that when they put it back on, diagnostics claimed it was only 21% clogged, but still regen would not work. DPF light was still on and it went into limp mode not much time later. This then lead them to try and run it without the DPF at all. I have no idea if they did any programming work or not, but I reckon not, hence why this did nothing, like you said.

 

I've read a bit on other threads regarding fault DPF sensors stopping the regen process. But i'll get fault codes before we go down that route. However, the dealer claimed that diagnostic measurements did not point to a faulty sensor. However, I'm pretty sure they were intent on trying to sell me a new DPF!

I can only echo what others have said, the fault codes are vital here.

 

What diagnostic equipment did the original garage use? Anything other than VCDS won't provide the proper detail.

 

http://wiki.ross-tech.com/wiki/index.php/Category:Fault_Codes

What diagnostic equipment did the original garage use? Anything other than VCDS won't provide the proper detail.

 

No idea, sorry.

Guys,

 

Will VCDS-lite and the appropriate cable be OK? I'm guessing OBD2 codes won't do.

 

I'm not very keen to spend lots of money getting the full VCDS and cable. 

Try an odb2 Bluetooth gadget (less than a tenner) and a free app on your tablet in the first instance to see if there are any codes picked up. If there is anything at all, it won't regen and any picked up codes may give you a better clue as to where to start looking.

No need to buy your own, check out this map to find a friendly member close by.

 

A few beer tokens normally does the job...

 

http://www.briskoda.net/forums/topic/262215-list-of-vcds-owners-previously-known-as-vag-com/

No need to buy your own, check out this map to find a friendly member close by.

 

A few beer tokens normally does the job...

 

http://www.briskoda.net/forums/topic/262215-list-of-vcds-owners-previously-known-as-vag-com/

  That's awesome. PM already sent

OK, still working on getting VCDS on the issue, but for the time being I've pulled the OBD2 codes:

 

P0135 - Powertrain - O2 sensor heater circuit (bank 1 sensor 1)

 

P2002 - Powertrain - Particulate trap efficiency below threshold bank 1

From the Ross-Tech site

 

 

17443/P1035 - Sensor for Nox (G295): Signal Implausible

Possible Symptoms

• MIL on

Possible Causes

• Sensor for Nox (G295) faulty

Possible Solutions

• Check / Replace Sensor for Nox (G295)

Special Notes

• Check Mesuring Blocks. Specification 0 - 90. The new Sensor goes down to -40

 

 

 

18434/P2002/008194 - Particle Filter Bank 1: Malfunction

Possible Symptoms

• Malfunction Indication Lamp (MIL) active

Possible Causes

• Exhaust Pressure Sensor (G450) faulty
• Diesel Particle Filter (DPF) faulty

Possible Solutions

• Check/Replace Exhaust Pressure Sensor (G450)
• Diesel Particle Filter (DPF)
  • Perform Emergency Regeneration (Refer to Specifications!)
  • Check/Replace Diesel Particle Filter (DPF)

Special Notes

• Skoda Superb (3U) & VW Passat (3B) (Engine Codes: BGW, BSS, BWW) had issues with faulty Exhaust Pressure Sensors (G450), they were defective from factory and due to a leaking sealing the measured values were incorrect and resultet in wrong calculated particle filter load and unsuccessful regeneration cycles.
• With CBEA and CJAA engines, the factory documentation may show the wrong part location for the Exhaust Pressure Sensor 1 (G450). This sensor is in a foil pouch just behind the oil cap.

The beauty of VCDS.

 

All the effort from the garage and the dealer wasted.

 

Replace both sensors (approx. £50 each) and see where that gets you. Both these sensors (G295 & G450) are known weak points.

 

Depending on how long they've been faulty will depend on the condition of the DPF, the duff senors will have prevented the DPF from regenerating properly.

 

Worst case scenario it's a DPF removal at £500.

Thanks to all you guys.

 

Hopefully, after the initial DPF clean by the first garage, the DPF shouldn't be too badly clogged. 

 

Is any re-calibration required when replacing these sensors? Will I need to get VCDS on the job?

Unfortunately, you need (as far as I've heard). That's in case you change them yourself.

Otherwise the  garage might do that.

Thanks Jevpls, I seem to have lost faith in garages recently.

OK, finally got commitment out of a great forum member to help bring VCDS along and help out. He's never done a DPF sensor adaption and I'm not even sure what needs to be done for the Nox sensor. Can someone point me to where we can learn about how to do both these jobs?

 

Cheers.

bump

The dpf differential pressure must be adapted before the engine is started. Doing it is dead easy, go into the engine controller then choose adaptions and pick it from the drop down list.

I don't know about the nox sensor.