Diagnosing Vnt Turbo Issues - Heads Up!

[ClassicFan]

So I finally fixed my turbo limp home issue, but not in the way I expected!

 

I was completely thrown off the scent by the diagnostic errors so thought this might be useful to someone.

 

The car was showing overboost and N75 open/short to ground intermittent errors.

 

First thing I did was vacuum test the lines and check the N75 terminals - all good.

 

So I thought, it's probably a failed N75 and a clogged turbo.

 

New N75 valve fitted and the intermittent fault went away, just the overboost was left.

 

So before totally stripping the turbo I tried some oven cleaner to see if I could avoid the teardown.

 

This significantly improved things, no overboost fault, but.... The N75 fault was back!

 

So I resigned myself to stripping the dash as I thought it must be a wiring issue from the N75 to the ECU. A clogged turbo couldn't cause an N75 open/short fault right?

 

Wrong!

 

A long run later (8hrs) purely by luck has totally cured the turbo issues. 1 month later and still no problems. So take note, and don't believe everything the diagnostic companies tell you about fault codes and their causes.

 

Hope this helps someone!