Oil Temperature Sensor For ECM: Testing and Inspection
Oil temperature sensorElectrical oil temperature sensor diagnosis
General Description
The purpose of this diagnosis is to detect electrical faults as defined in OBD I requirements.
To avoid wrong error detection in cold conditions, the diagnosis is only done after a delay time after engine running or if engine coolant is warmed up.
To avoid wrong error detection in hot conditions, the diagnosis is only done if engine coolant is not to hot.
Error Symptoms
- Short to battery or Open circuit
- Short to ground
Flow chart: Electrical oil temperature sensor diagnosis
Oil temperature plausibility diagnosis
General Description
This diagnosis is performed in order to detect a not-plausible oil temperature signal.
The diagnosis basically involves the comparison of the oil temperature sensor-signal to a plausible temperature range based on ECT sensor signal.
Two diagnoses are distinguished:
- Signal to low after delay time at hot engine
- Signal to high at cold start
Error Symptoms
- Signal too high
- Short too low
Flow chart: Oil temperature plausibility diagnosis - signal high
Flow chart: Oil temperature plausibility diagnosis - signal low
