Loss of power in BMW

Recently power is lost when driving my BM3 at around 2000 revs to return normally shortly after. My independent garage diagnosed and fitted faulty air control valve without success. A new diagnostic test apparently showed protective switch of turbo faulty, again no success. Now suggesting problems with turbo, my original gut feeling. Before committing to further expense any ideas please and likely cost?

Asked on 20 June 2015 by Derek Jones

Answered by Alan Ross
Well sounds as though the engine is going into "limp mode". The reason for this could be a number of things.

You say your local garage diagnosed, so did they actually carry out a diagnostic check and if so what were the fault codes(i.e P ---- 4 numbers). Normally a diagnostic would show what the fault was.

We would suggest you check with the garage and find out if they did carry out a diagnostic and if not why not,as "limp mode" could be quite a few things especially one of the many sensors fitted to the engine.
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