Monitoring description
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2008 BMW Z4, 2008 BMW X5, 2008 BMW X3, 2008 BMW 528xi, and 2008 BMW 528i. However, it is still accessible from the selected car via links, so may be relevant.
Depending on engine speed, valve-lift, inlet camshaft position, outlet camshaft position and manifold pressure an air mass flow into the cylinder is calculated. There is also a correction of the calculated air mass flow depending on intake air temperature, coolant temperature and ambient pressure. The ratio between the measured air mass flow and the calculated air mass flow must be between adjustable MIN/MAX-values. If the MIN/MAX thresholds are exceeded, a time counter is incremented. After this counter reaches the threshold within one diagnosis cycle, an air mass flow meter malfunction is detected.