Hey,
I'm new to the forum and also recently become the proud owner of a 2014 A6 C7 3.0 TDI. Unfortunately things haven't got off to the best start though and I am having trouble diagnosing the issue, any advice or help would be greatly appreciated!

The issue
On a cold start I noticed a very slight missfire coming from the engine that lasts for around 10 seconds and stops, There are no warning lights, no smoke, no knocks rattles or any other issues. That said the car has just surpassed 100k (only just) so I thought I would start with the obvious thing and replace all 6 glow plugs. After some wiggling back and forth and lot of WD40 later I successfully changed all 6 plugs without snapping any (yay).. Unfortunately though the next morning I felt the exact same missfire and even asked my partner who was sat next to me if she could feel it (to confirm I wasnt going mad).. She confirmed she felt a slight "shiver" as she descrivbed it which again lasted around 10 seconds and stopped... Getting a bit anxious this was a more serious problem I plugged in my OBD11 reader and scanned the car, it returned the fault code - P067F00 Glow Plug Circuit High Cylinder #6.

Since then I have been researching any common issues and supprisingly found nothing or very little. A mechanic friend said it may be the glow plug relay or control module - I have been unable to find anything indicating where that might be located on one of these or if that could even be a cause. A little bit stuck at this point and looking for any advice or pointers really, or to see if anyone else has had a similar issue!.

Cheers!

Audi A6 Saloon, 2014 3.0 TDI (204bhp) - 101,000 miles

 

I'd check the glow plug control module. It looks more like a relay than a control module. In the US the part number is 4L0 907 282 A. It should be located inside the engine bay electrical box. You can use a multimeter to test the circuits in the module.

 

I've now managed to locate the Glow Plug Control Module / Relay. I found there was very little information out there on this so have included some images and tips which may help others experiencing similar issues.

On my vehicle the relay panel was located in the bulkhead area on the drivers side (Right Hand Drive). To get to it you'll need to remove the black trim that covers the bulkhead. This can be removed very easily by removing the rubber seal then gently wiggling the plastic trim out.

Once removed you'll see the ECU unit is covering the relay panel. This can be removed and gently placed to one side by pulling the plastic clip which holds it in place.

Once the ECU is out of the way you'll have access to the relay panel, it's a sealed unit and you'll need to remove the 5 torx screws. Once the lids off you'll be looking for the relay numbered 651.


Glow plug control module (651)

The part number is: 4L0 907 282 A I looked around and it seems this part is not readily avaliable, so I called Bosch who advised me that they hold the patent on this part and only supply it to Audi, so you'll need to order it through your local main dealership. Im in the UK and was quoted £97.43 for a replacement.

Here's a view of the pins, you can see the glow plug circuits labelled #G1 - #G6

Glow plug module

 

Glow plug module replaced which has resolved the issue! Audi informed be that the part number has been superceded by part No: 4L0 907 282 B