sushilovin

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

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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?

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