BMW Engine Fault alerts when engine revved abruptly

[bnovenario]

I have a BMW 520i 2004 with an inline 6 2.2L engine. I had the software upgraded recently. Now everytime I rev the engine abruptly the cruise control failure message appears and shortly after the engine fault failure appears after which the engine is slowed down. I have to turn the engine off and on again to bring it back to normal. I have brought it to BMW and they replaced one high tension cable but the problem still happens. They have run the diagnostics on it but they say nothing appears. I have brought it back and showed them the problem but they have yet to come up with a diagnosis. Thanks.

[marti5]

Well, if I was you I would go back to the person whom upgraded the software and I sure they will be able to sort it, I hope you had it done by a professional and not just a dodgy back street garage, as ive heard of this before, with the car ending back at BMW to sort it out, Remapping the whole car.

[bnovenario]

The upgrade was done by an authorised BMW dealer actually and I brought it back to the same shop and they said there was nothing wrong with it until I demonstrated the problem.

[marti5]

Well in that case it is down to them to sort it out.