New User Introduction

[bobbyb]

Hi All,
Great forum.

I've been using some of your experiences to try and get to the bottom of an overboost problem P0234 (Limp mode at high load in 4/5th gears) on my VW T5 1.9 2006. I've already run a cleaner through the turbo and checked all the vacuum lines. the Actuator moves OK but I'm going to remove it and give it a thorough clean/test next.

Going to try some of the forum checks and tricks 1st but I may be back soon for some more advice.

Stay Happy

[Keithuk]

Welcome to the forum Bobby.

EOBD II Error Code: P0234

Fault Location:
Turbocharger (TC), engine boost condition - limit exceeded

Possible Cause:
Hose connection(s).
Wiring.
Turbocharger (TC) wastegate regulating valve.
Turbocharger (TC) wastegate.

As taken from my Free EOBD II Error Codes software

[bobbyb]

Hi Keith,

Thanks for the response, I seem to be Chasing my tail on this one? I was convinced after checking the easy things that my overboost problem was due to sticking VNT vains, so I spent yesterday under the van removing/cleaning refitting the turbo.

The vains were sticking at one end of the travel so, I was convinced that the repair would cure the fault, however imagine my surprise when i take her out on a test drive this morning to find exactly the same issue, no change in the fault whatsoever?

I ran with VCDS on map mode as described and in the forum, the figures back up the fault, at full throttle the actual boost will climb way above the requested to about 2550mb before the Limp kicks in.

As the requested boost levels off the actual boost just seems to carry on upwards despite the duty cycle dropping to its lowest value??

I have used VCDS to check the actuator valve operation, which works fine.
During turbo cleaning the VNT vains moved freely through complete range.

I'm really at a loss now any advice what to try next?

Stay Happy