Engine Coolant Temperature Sensor Monitoring

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.

RangeCheck






PlausibilityCheck lowside
The engine coolant temperature is plausible, if:

(reference temperature - threshold) < engine coolant temperature






PlausibilityCheck 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: