Hi, I have an E46 318iSE. The yellow 'engine' light came on mine occasionally. Stalled a a few times etc. and was difficult to restart. When the local garage interrogated the engine management system he found out it was the cam belt position sensor that was faulty. £135 to remedy (incl. labour). Unfortunately, the 'little yellow light' hides a multitude of things. I have heard that switching the igintion on and off a dozen times resets the system but I can't verify that's true unfortunately.
Regards
Tony
Tony
February 2008