Another DPF issue

[john7625]

Hi folks, sorry this is a bit of a long post but I wondered if any of you good people would be able to offer me some advice I have a 2006 A3 2.0 TDI 170 I have been having major dpf issues, about 3 weeks ago the car started to randomly go into limp mode then bursting back into life, eventually I lost all power and had to get the car towed my local mechanic who found the dpf completely blocked.

He had it cleaned and refitted. He also replaced the G450 sensor. When I got the car back it was running better than ever for about 5 miles then the dpf warning re appeared then the eml light came on and finally the flashing glow plug light. The car was permanently in limp mode and can't rev above about 2500 rpm.

The mechanic has told me he cant fix this "new issue" and I need to get an auto electrician as his work is all good. I have have read a lot on here and it seems the new sensor should have been adapted so I paid a local company to do a diagnostic and he says he adapted the sensor, but I'm still getting the same problem.

I found some info on the sensor voltages and done some testing it appears theses voltages are correct pin 1 is +5v pin 2 is gnd and pin 3 is sitting at about +1v when the engine is switched off.
it rises to about 1.2 volts when running.

The thing I'm finding strange is I get the flashing glowplug light as soon a I turn the key before the engine is even started so I cant help think this might be a faulty sensor, also found if I disconnected the sensor the car comes out of limp mode but has the dpf warning light and eml light on.

Thanks in advance....

[nikkibriggs]

Hi, sorry to jump on your question but if you find the answer can you please let me know as I've had my car around 12 weeks and having same problems and been back to the garage 6 times, twice on tow truck, new sensor still not sorted and my glow plug light sometimes flashes after just turning ignition, maybe a common fault, thanx, Nikki

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[john7625]

Hi, I still haven't managed to get to the bottom of this issue. Since I posted this I have removed the ecu (which was a huge pain because of the anti theft cage its fitted in) and traced the three wires from the sensor using the electrical diagram, and all the wiring checks out ok, no shorts or breaks in the wiring. I'm going to order a new sensor at the end of January just to rule that out because there are 2 versions of the sensor - 076 906 051A or 076 906 051B the sensor fitted on mine should be the A version but it doesn't have a part number printed on it so I can't be sure.

I'm still driving the car with the sensor disconnected and so far it's running fine but I'm guessing it's just a matter of time till the dpf becomes blocked again.

[men8idw]

I am interested to see how you get on with this. I am having exactly the same problem on my Audi. I have run a VCDS which is indicating an implausible signal (indicating pressure sensor) and the spot loading is generally floating between 10-20mg (although has just crept up to 45mg).

At a loss as really don't want to be digging deep in the pockets for a new DPF.


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[john7625]

I ordered a new G450 sensor yesterday its due for delivery tomorrow (Friday) I will let you know how I get on. My VCDS output came back as implausible signal when this fault first occurred. After the sensor was replaced this changed and now says signal too high.

[men8idw]

Have you adapted the new sensor? Not sure if that is required or how you would do it


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[john7625]

Yeah I initially paid to have it adapted by a local company. But I now have access to vcds so have actually tried it myself so i know for sure it's been done.
I have also reset the ash mass values using vcds since this should have been done when the dpf was cleaned.

[men8idw]

How do you do the adaptions you describe above? After an hours drive and logging with VCDS I can see that the DPF is regenerating on a fairly frequent basis (every 10minutes or so). After clearing the faults only the implausible signal from pressure sensor has reappeared.

I am tempted to source a new sensor and install tomorrow.


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[john7625]

I'm not sure if there are any rules that stop me from posting this - This info comes from the ross-tech wiki page if you google it you will find it.

CAN Protocol (G450) procedure

Instructions should be populated in a pop-up balloon when connected to the controller in question with VCDS.Key ON, Engine OFF
[Coding-2] or [Login-II] button
Enter the code shown in the VCDS pop-up balloon
[Do It!]
Switch Ignition OFF for 30 seconds
After the key is cycled back on the adaptation should be completed

[men8idw]

Ok thanks. I will have a google today.


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