Turbo under boost mystery....

   #1  

J0N

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Good evening all,

A while back I posted a thread asking for advice regarding issues surroundimg adapting a non pieburg EGR for a VW Sharan 2.0tdi blue motion. This has since developed into a raging nightmare that's potentially nothing to do with the EGR.

So I'll start from the top....

Driving the car on a bypass with a reasonable gradient doing 45mph in 5th and the engine dropped into limp mode. Read the code with VCDS..P0403 - EGR valve open circuit. Where I work has a trade account with a reputable auto spares store so I phoned up, gave them the reg plate and they dropped me an EGR module (valve, cooler, diaphragm...whole unit) off. So fitted this on the drive assuming all would be sweet......

The next day under similar conditions to the initial limp mode (gentle gradient, 45mph in 5th) it drops into limp mode again. Again read the codes on the spot with VCDS P0299 - turbo underboost. Quick look through the forums leads to issue being either non-genuine EGR at fault or may require adapting. Had a flick through the settings and measuring blocks with the VCDS to no conclusion other than an error message.

By this point I was heading back into my shift pattern so I take it to the local VW specialist.

He smoke tests the boost system and finds a small split in the intercooler. Replaced this and take the car out for a drive, same issue.

He ended up having the car for three weeks as the shear stubborn determination in this chap was purely admirable.

- The turbo was removed, refurbished and refitted.
- New N75 valve fitted.
- New boost pressure sensor fitted.
- New turbo actuator straight from VW fitted.
- The whole vacuum system has been smoke tested and all vacuum operated components check with mitivac.
- Clamped the vac pipe to the EGR for a test drive... leading to actually fitting a full blanking kit just to rule it out...still drops into limp mode.
- Auto electrician has been out to test all....ALL the wiring under the bonnet.
- New fuel sensor of some description (unsure which one as it was a code that flagged up on a test drive while he had the car)

He got to the point where he couldn't find anything else even slightly the matter with it and to continue was un-economical for him as he only charged me for the intercooler and the rest out of his own pocket.

I'm at a bit of a loss now without sucking it up and heading to VW or clearing the codes and part ex-ing which really would break my heart.

Any thoughts or info much appreciated.

Cheers guys!
 
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   #2  

stefdds

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I would definitely post a full and unedited Autoscan as you never know what someone in the community may notice.
 
   #3  

J0N

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The car is currently still at the garage awaiting collection hopefully tomorrow if I'm free, otherwise I would've post one with the thread. I've made this post on a conversation I had with the garage owner an hour ago.
 
   #4  

JK@OEC

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My deepest sympathy Jon, i have a 2kcaddy that has the same problem. I have been struggling with it since November last year, spent a fortune and more hours than i can count, still no further forward. If you get a solution i will be most grateful if you post.
 
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