Engine Coolant Temperature Sensor Monitoring

Engine Coolant Temperature Sensor Monitoring

The engine coolant temperature is electrical O.K., if the following condition is true:

Diagnosis threshold min. < engine coolant temperature < Diagnosis threshold max.

Range Check







Plausibility Check lowside
The engine coolant temperature is plausible, if:
(reference temperature - threshold) < engine coolant temperature







Plausibility Check highside
The engine coolant temperature is plausible, if:
(engine coolant temperature - reference temperature) > threshold







Stuck Signal Check
The engine coolant temperature is plausible if - after subsequent periods of vehicle operation at high and low cooling condition, respectively - a certain amount of variability in the engine coolant temperature signal is observed.
(engine coolant temperature(max) - engine coolant temperature(min) > threshold.







flow chart: