CAN based Ambient Temperature - signal diagnosis: 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 purpose of this diagnosis is to detect electrical faults as defined in OBDII requirements. The input signal is a CAN message of instrument cluster. If an error is detected by the instrument cluster, the error symptom is sent via CAN to the ECU. The ECU then debounces the error and stores it in the error management.