Engine off timer monitoring: General 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.
The engine off time is calculated using a relative time counter obtained from the instrumentation via CAN message. The difference in value of the relative time counter at last engine stop and at current engine start is compared to the corresponding values of ECT. An error is detected when engine off time is adjudged too small after a relatively large drop in ECT, or, conversely, when engine off time is too large after a small drop in ECT.