Resetting the ECU

[Ramblin MAn]

Found this on another site. Very relavant and a little different that what I knew.

FLUCTUATING, EXCESSIVE IDLE SPEEDAFFECTED MODELS: All vehicles with Bosch Motronic fuel injection system.FAULT: Fluctuating, excessive idle speed - engine starts after charging the battery. CAUSE: If the battery is disconnected or discharged the Motronic control units lose their programmed and stored
basic adjustments. SOLUTION: When starting the engine after the battery was discharged or disconnected, switch on the ignition
for approx. 10 seconds and then switch it off again. This makes sure that the old adaptation values are deleted
and stored again in the control unit. After this the engine starts without problems and the above symptoms do
not occur again.


I have not been doing that.

[Jorgeconrico]

This may be a dumb question, but are you talking about turning the car all the way on and then shutting it down?

[DesertEagle]

when I googled some of the phrases for the instruction on resetting the ecu, I only found this warning in reference to VW's.  Is anyone sure this applies to M42 BMW's?