Audi 2.0TDI - No boost and engine light - EEK!

[Ray Singh]

Dear Audi experts.

My wife has a 57 plate Audi A6 2.0 TDI avant.
I was allowed to drive it today for the trip to Ikea !

As soon as I got in, I could feel that it was really under powered. One of the hills close to home has a pedestrian crossing. We had to stop on the incline and the car really struggled to pull away and get up to speed. It was almost like the car was not boosting.
This continued and I pulled over at the first safe point. No warning symbols, but just no boost except on a rare occasion when it behaved as normal.

When I switched off the car and then back on again, the emissions control light (yellow engine symbol) has lit and stayed on within the dash.

Any ideas what this could be? I have the car booked in for inspection on Monday, but would like to go in with some knowledge.

Thank you and happy new year!

[JeffC]

could be anything , air flow meter, sensor , will have a fault code so get it plugged into Vag com, the last two I have seen on 2.0 tdi s have come up with over boost problem and both needed replacement turbos.

[fatboy b]

That era 2.0 tdis also suffer from split intercoolers, or could be an intercooler pipe that has just come off.

[VDubMatt]

If its engine code cbab or similar 2l TDI just take the vacuum pipe off the turbo actuator which you can easily get to from the top, find some pipe that will fit on it and suck the pipe...of the pipe produces a vacuum against your tongue the actuator is OK, if not it'll be the actuator and then take it to your nearest dealer and get a software update done! Actuators are easy enough to do by an independent but they'll need to know the parameters to set it at etc.
If the actuators ok I'd check all vacuum hoses first for kinks and leaks etc

[Ray Singh]

Thanks all that took time to reply.
The car is with Audi main dealers now for an insepction on Monday.

I will reprot back with further information.

[Ray Singh]

Received an Audi Cam e-mail this morning.

Technician talking me through the issues:

1) Vaccum unit on intake manifold not holding vaccum.
2) EGR valve is siezed.

Both items need replacing.

I have called them up to obtain a quote, but technician or service rep are busy.
Any ideas how much this will set me back?

Is it worth asking them to try to free up the EGR valve?

[Ray Singh]

Some prices.

Vaccum unit ~ £300 fitted.
EGR ~ £400 fitted.

Total pain £700.

I have asked them to keep aside the original seized EGR, so i can take a look at its operation.

[Ray Singh]

Collected the car today. Spent nearly £800.
The car drives a lot better - much better performance.

[CDP]

Ray Singh said:

Collected the car today. Spent nearly £800.
The car drives a lot better - much better performance.

Glad to hear you had a result; the dealers never worked out what was wrong with my Vectra.

This is why I bought a non turbo petrol car to replace it. The fuel savings are so easily wiped put by the bills a TDI can produce.