2007 BMN Diagnosis thoughts Boost, Intake or EGR?


New member
Jan 4, 2020
Dumfries and Galloway
Audi A3 2.0TDI 170PD BMN

I recently got a P0401 Exhaust Gas Recirculation (EGR) System: Insufficient Flow Detected.

Stripped and cleaned the EGR but mil light returned on test drive. When I cleared the fault when warm, mil light did not return during several hours of driving until cold start. Then back on.

Cleared the fault again. Did not return

When on the test drive I was on the motorway during heavy rain with cruise control in and hit a patch of standing water which caused the ESP to kick in, cut out the cruise control and drop revs - it did it's job.

Immediately after, MIL light came on and car went into limp mode.

Limp worked for a while - going up hill with some weight in the boot - but then slowly died off, started to cough a bit and finally stalled out on an ext ramp up hill. During this time the DPF load coefficient started to climb quite quickly (ie pressure differential over the DPF) and was up to 54% by the time it stalled out.

The engine would then not restart.

Fault code P0299 - Boost Pressure Regulation: Control Range Not Reached was now logged on VCDS.

So far all I have been able to do is use a vacuum pump to check the turbo vane actuator which appears to be moving freely.

Anybody got any thoughts as to what may have caused the death here? Any ideas on further diagnosis with an engine that will not start?

Thanks in advance