2010 1.6 TDCi Underboost - super low VGTDC value (~5%)

Recommended Posts

Hi folks,

First post here. I bought a 2010 Focus 1.6 TDCi (108) around mid August, knowing it had some issues. EML is lit and my diagnostic plug in gives two codes: P042F EGR stuck closed and P0299 Turbocharger Underboost.

I have been monitoring both issues separately while driving to try to diagnose the faults as I don't believe they are related and EGR is easy enough to sort out.

I noticed a few days ago that my OBDII app detects a sensor for VGT Duty Cycle. I started tracking this and noticed that (once the warm-up cycle is complete and the EGR duty reads zero) the VGTDC sits at around 4.8% all the time. Yes, FOUR percent.This is regardless of whether I am at idle or WOT. I understand this means the turbo is basically fully open all the time?

Restarting the engine causes it to jump back up to around 70% at idle, which it pretty much normal from what I hear, with normal WOT reading around 40% (haven't tested my own "normal" WOT as EGR opens again too). I have suspected the turbo solenoid (or Turbo Boost Regulator Valve, as Ford calls it IIRC) for a while but haven't had it replaced yet. 

What would cause the VGTDC to sit so low constantly? Should I just go right ahead and replace the solenoid or try other things first? Any insight would be massively useful and appreciated. I can attach data if needed, I have collected a lot over the past few weeks. Thanks!

TL;DR: VGTDC sits at 4.8% at idle and WOT. Correct values should be around 70% at idle and 40% at WOT, from my research. Why?

Share this post

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.