Hi everyone,

I have an Audi A6 2.0 TDI (2015) and recently I’m getting these error codes: 

P029900

P0AFF00

P256300

 

The car sometimes loses power (limp mode), but when I turn it off and on again, the power comes back for a while.

 Does anyone know what could be the cause of these faults? Is it usually the turbo actuator, or could it also be something else?

It could be a dying battery.

23 hours ago, Rudi08 said:

 

Hi everyone,

I have an Audi A6 2.0 TDI (2015) and recently I’m getting these error codes: 

P029900

P0AFF00

P256300

 

The car sometimes loses power (limp mode), but when I turn it off and on again, the power comes back for a while.

 Does anyone know what could be the cause of these faults? Is it usually the turbo actuator, or could it also be something else?

Hi it could be a faulty MAP and MAF sensor if its the turbo you will have to buy a new unit so try the sensors first. 

Steve.

1 hour ago, Stevey Y said:

Hi it could be a faulty MAP and MAF sensor if its the turbo you will have to buy a new unit so try the sensors first. 

Steve.

Thanks Steve, but if it was the MAF or MAP sensor, wouldn’t I also get specific error codes directly related to those sensors?
 

At the beginning, when the issue first appeared,I had these fault codes

If it is the actuator, unfortunately it’s not practical to replace as it needs to be set up and calibrated which is specialised. The actuator can be tested with a vacuum pump to see if it holds pressure. VCDS may be able to show live date if you have access.

If you need to replace the turbo check out https://turbo-diesel.co.uk

That’s genuine new turbos, not remanufactured (although you can get them), Garrett, etc, at half the price Audi will charge for basically the same product, not including fitting.

You’ll need exhaust gasket, plus get a new oil feed line, as they always leak at the union nut to the turbo. 

23 hours ago, Rudi08 said:

Thanks Steve, but if it was the MAF or MAP sensor, wouldn’t I also get specific error codes directly related to those sensors?
 

At the beginning, when the issue first appeared,I had these fault codes

Hi if the MAF and MAP sensors information dont add up to what the ECU expects it goes in to default strategy and wont allow boost from the turbo, its all about the correlation between the two sensors the MAF can be on its way out but not throw a code, same with the MAP just thought I would suggest this as the cheaper options before going for a new turbo, both sensors get weak at about 80k.

Steve.

Hi Stevey, I managed to sort out the problem — it turned out to be the vacuum sensor (attached in the photo). Luckily it was a cheap fix, only about $40. Thanks again for your help!

Thanks for letting us know. You mentioned a price in dollars so does that mean you imported it from America?

I'm getting these too and already replaced vacuum selonid and no improvement.....