TDI Loss of Turbo / EGR Issues

**dingledell** · 05-07-2015,08:24 PM

Hey All,

I have a '06 A4 B7 Avant 2.0 TDI 140.

Last Tuesday I was driving home from work when all of a sudden I lost turbo power- shortly followed by an 'Oh Crap'! (Edited Version) but then it came back again! It did this a few times until the engine light come on and then it never came back again

So after a few reads on the forum, I discovered it could be the EGR valve. So I whipped it off and sure enough not only was it full of carbon but the teeth on one of the cogs had worn down so it could not engage. A day later and I had a new valve fitted and took her for a drive and all was well in the world again! I still had the CIL on but I would solve that the next day when I would buy a EODB hand scanner.

The next morning when I left for work and started the car, the CIL went out by itself, result! Drove the 30 minutes to work and no issues. I headed out for lunch and then the dreaded loss of turbo happened again but only for a minute or so, once it returned it didn't go again. The same thing happened again on my way home from work. At this point I had the hand scanner which I picked up at lunch. I was getting codes P0404 & P0405. I cleared them but P0404 keeps returning.

I had read that a new EGR valves needs to be run through a process via VCDS so the car can learn the ranges of the new EGR valve. I found a VCDS user and set off for Bristol (a 50 min drive) sunday morning. The car was cold when I set off and I never had an issue all the way. We checked for error codes and nothing came up (I had cleared the night before), so car was good. We ran the car through its test where it rev'd itself for a while learning. After this we checked for errors and P0407 had triggered and VCDS was pointing it's finger at the Lamba sensor.

When I headed off again, no turbo power for a couple of minutes then it came back and all was well for the remaining journey. I stopped to fuel up and again no turbo when setting off but after a couple of minutes it was fine. The same thing happened again after a stop at Tesco. So It seems fine if it starts from cold but starting warm it takes a few minutes for the turbo to kick it.

So if you have read to this point, THANK YOU!

Could it well be the Lamba sensor causing this? It does seem to be a sensor issue don't you think?

I'm ordering VCDS myself so will have this in a couple of days. So I don't have the output from VCDS.

Any help or suggestions would be greatly appreciated!!

Thanks

**doctordubs** · 05-07-2015,08:32 PM

Hay man. Had many similar probs on different platforms. Best advice. To remove the entire egr system, incl intake manifold, and clean the crap out of it. Ul see the buildup wen u start stripping. Trust me.

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**doctordubs** · 05-07-2015,10:39 PM

My reason for above advice?? Its a pain job, but, its the cheapest. And in lots of egr/flow related issues a cleanup is all that was needed.

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