Emission (lambda) control. The "0A" code is the fault code that comes up on my 89 535i 5-speed. The car runs and drives fine. Been driving it for a week now since I put a used ECU from a 89 737. It actually seems to run and drive better than the remanufactured one that was in when I bought the car. That ECU fault list came up "--" no faults. I don't have the remanufactured ECU anymore...ruined by me. Anyways, I'm new to BMW's and could use some help...anyone know?