A4 TDI 110 (AFN) Overboost caused by timing

[AutoTDI]

The exhaust restriction was throwing intermittent manifold pressure, and MAP error codes.

In this thread: https://www.vwaudiforum.co.uk/forum/s...ad.php?t=18322 you reported that one of these MAP fault codes was: "short to B+", which looks very much like a MAP hardware problem. Is it possible that this code could be thrown as a result of an exhaust restriction? Of course, we don't know what the actual process is for generating this code so I suppose anything is possible. It would be nice to have a software flow chart showing what the effects of all these sensor measurements and diagnostics have on actual fuel delivery and turbo boost. I assume that the firms which re-map ECUs and/or sell power chips have all this info, but where do they get it from?

[ini]

The "short to B+" MAP fault code was thrown every time my car went into limp mode.

The fault description makes it sound like an electronic or wiring fault, but replacing the CAT solved the power problem, and the code never returned.

[AutoTDI]

Just goes to prove that you can't jump to conclusions when interpreting fault codes. I haven't checked for fault codes recently as the engine is fine - let sleeping dogs lie!