Audi A4 Glow plug circuit problem

AeroEng1

Before I bought the A4 (2006, 2.0 TDI, 140BHP) about a month ago, the EML was on so I read the codes which were:
P0670 Glow plug circuit fault.
P0671 Glow plug #1.
P0673 Glow plug #3.

The seller replaced plugs 1 & 3 and all was good.

2 days later the EML came on again showing the same codes..

So I decided to swap plugs 1 & 2 with each other to see what happens. Checked the part numbers all correct and you could see that 1 & 3 had recently been replaced.

EML on again, this time only showing P0670. So I put the plugs back in their original position and waited for EML to reappear the next day. Read the codes and again only showing P0670, which proves the plugs are all good.

So yesterday I replaced the Glow plug/Injector wiring harness, and again today the EML appeared showing code P0670.

I’m thinking now that maybe its the glow plug relay.
Anybody have any idea where the relay is located or have any other idea what the problem might be?

AeroEng1

Anybody have any ideas for me??

George Dalton

Were genuine glow plugs fitted?

AeroEng1

ya genuine plugs, with correct part number.

George Dalton

What are you scanning it with? Does the car have a DPF?

AeroEng1

A mate of mine has some sort of a chinese copy of a vag com for his laptop. Its never let me down before and I have been using it for a good while now.
From a quick google the 140bhp does not have a DPF but I dont know where it would be located if my car has one?

George Dalton

I mean particulate filter. I think only the 170bhp TDI B7s had one so you probably don't. What is your engine code? Edit: I see yours is 140bhp so no DPF.

Do you have the 5 or 6 digit VW fault code number or just the P code?

The fuses and relay for the glow plugs are in the engine bay fuse box, which is located at the base of the windscreen under the bonnet on the right hand side, you need to remove the wipers and the plastic trim from the base of the windscreen to remove the cover from it.

AeroEng1

My engine is BRE.
I only have the P code.

Do you think it could possibly be the relay, as I know someone with the same car and could borrow his relay to try it but I dont know where the relay is located. How would I know which relay it is?

AeroEng1

I was just looking where you said there below the wipers. Theres a black square cover over the ECU which I took off for a look before. I can see all the way in behind that below the wipers and it doesnt look like there is anything there.

AeroEng1

I have removed the ecu cover again and taken some pics. All that seems to be there is the ecu and 2 fuses. I cannot find the glow plug relay.

George Dalton

Did you look underneath the ECU?

AeroEng1

I was kind of afraid to remove the ecu but I looked down beside it and it didnt look like there was enough room for a relay.

How do you remove the ecu? is it screws or what?

Will it throw a load of codes when removed?