Looking for some advice on my A6 3.0tdi

[James301176]

Hey all..

first time post post so excuse anything that's not the done thing on the forum.

Ive just replaced my 2.7T quattro with an 05 3.0tdi avant Quattro.
The car is going back to the place I bought it from but wanted to get a bit of background info so I can ask them what they intend to check.

Basically I have the emissions light on. I've reset the fault with Vagcom and it stays of for a while then reappears.
the fault code is:

001592 throttle body actuator bank 1 (j338) implausible signal
p0638 002 lower limit exceeded.


no other fault codes are registered

a couple of symptoms are. Smoke from exhaust on startup. Disappears when engine is up to temp.
the revs at idling are sat at 800rpm but occasionally are hunting up and down.
engine is shuddering when shutdown.
mpg is less than it should be. On a 20mile run on the A1 sat at 70mph I'm getting 28mpg average.
strange whining when the accelerator is pressed not sure how to explain it and it seems only to happen for a few seconds then stops.
no gearbox faults.

apparently the garage changed the throttle body before they handed the car over but I'm doubting if they have or not. I think they just cleared the fault code and hoped it would stay off.

Any pointers would be really appreciated.

As as I say it's going back to the garage but I want to make sure they know what they're doing or at least be confident they have a clue about it.

thanks
James

[Scott K]

With a bit of luck, Gupsterg will be along to give you some advice. He has gone through this and would be well placed to let you know what to look for. Have a search for his posts/threads as well. The main worry for me would be if the injectors are shot-some of the early 3.0 engines are prone to this. If it is this, then you would be as well to return the car to the garage and get something else. Your mpg is well down-on a run like that I was getting almost 40mpg.

[James301176]

Thanks Scott..

I've had it down to Autotecnic in Sheffield and they've diagnosed it as the J338 control valve being faulty as well as going through the rest of the car. So at least I know what it is.. just need to get the garage to change it now. The part is £360 so not massively expensive but I'd prefer not to pay for it.
Rest of the car looks healthy though except the C links on the front end but no big deal. Oh and a fault with the autodim side mirror drivers side which looks like it has been smacked as its cracked.

So hopefully, once the unit has been changed all will be good! Just a few DIY bits to sort then..

I'll let you know.

[Lukenkarl]

Why diy? Surely they should stand by the warranty for the faults, but maybe not the cracked mirror if you didn't bring it to their attention when you picked it up

[Scott K]

The dimming mirror is very price you- keep an eye out at breakers. The c links are quick and easy to change. 30 minutes max and pretty cheap.
Good news on the faults. As Lukenkarl says, it should be covered by the garage. Good luck.