Coolant Temperature Stuck in Range 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 a coolant temperature signal that is stuck in high range. The diagnostic function checks if after a certain time engine stopped, the engine temperature has reached a plausible (low) value, i.e. the engine has cooled down.
If the measured engine temperature at engine start is above a calibratable threshold and the diagnosis conditions are fulfilled, the error is set. The threshold depends on Intake Air Temperature at Start and the Time Engine was stopped.
For RBM handling the Cold Start Denominator will be considered.