Can anybody suggest where to start looking to fix this fault (code came from a Peake fx5 - table 27 code Ab). My car has recently returned from main dealer after having the rear subframe mounts replaced (many thanks to this forum for all invaluable information) I now, occasionally get the engine management system light on, usually after a good run when the car comes to idle. The car shows no sign of problems physically - just the warning light.
Returned car to BMW they have checked and said tank and all ancilliaries have been put back correctly - don't know wether they looked at codes because the light was not on when it went back in.
Easy to keep resetting fault (Peake tool is excellent) but would like to get to bottom of fault.