Today’s featured repair is replacement of the Turbocharger on a 2004 VW TDI Jetta.
This TDI Jetta was brought to our shop barely running. Several repair attempts had been made by those with limited skill with no success.
As always, our first step is diagnosis: the check engine lamp was on and revealed a stored code for low sensor voltage. We traced this to a fault with the turbocharger vane position sensor. The engine sensors receive a 5 volt reference signal from the engine computer; we were only getting a 3 volt reading. That is until we unplugged the vane position sensor.
Unfortunately for VW TDI owners this part is only sold complete with the turbocharger so the whole unit was replaced.
While doing our diagnosis we also removed the EGR valve to inspect for excessive carbon deposits. What we found was severe and because of this we removed the intake manifold and cleaned out all the accumulated carbon deposits in the intake ports. So much carbon had built up that the ports, which are over an 1″ square, had been reduced to tiny passageways 1/8 of an inch in diameter.
Upon completion of these repairs the sensor voltage was restored and the engine ran powerfully.
Overall the VW TDI Jetta is a very solid and reliable car. The diesel engine is well built and makes for highly fuel efficient vehicle.
For more about the VW TDI engine click on this link. http://en.wikipedia.org/wiki/VW_TDI
For more about turbocharging click on this link. http://en.wikipedia.org/wiki/Turbocharging