Electrical Engine Coolant Temperature 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 of the sensor signal. The input signal is analog from a NTC and has to be in a calibratable range. Short circuit to ground can be detected immediately. Short circuit to voltage battery or open load is detected, if conditions of Intake Air Temperature and Time After Start are fulfilled. If an error symptom is detected, the error counter is de-bounced.