Fuel System Monitoring: Notes
WARNING: This page is about a different car, the 2003 BMW 760Li, 2003 BMW 745i, and 2003 BMW 745Li. However, it is still accessible from the selected car via links, so may be relevant.
Fuel system monitoring is an OBD-II requirement which monitors calculated injection time in relation to engine speed, load, and the pre-catalytic converter oxygen sensor signals as a result of the residual oxygen in the exhaust stream. Engine control module uses the pre-catalyst oxygen sensor signals as a correction factor for adjusting and optimizing the mixture pilot control under all engine operating conditions.