Coolant Temperature Sensor Test

5. ENGINE COOLANT TEMPERATURE SENSOR TEST:

A COOLER TEMPERATURE READING (HIGHER RESISTANCE) THAN THE ACTUAL TEMPERATURE WILL CAUSE A RICH MIXTURE


A. Compare the CONSULT readout to the actual engine temperature. Access this the same as for the ALPHA or MAFS reading, (touch start-> engine-> data monitor-> main signals-> [or ECM input signals] start-> now watch COOLANT TEMP/S). The coolant temperature should be comparable to like vehicles under the same conditions1 it should be within a few degrees of the thermostat opening temperature. NOTE: Self Diagnosis will only indicate an incident coolant temperature sensor if the circuit is open or shorted, it cannot detect an inaccurate temperature sensor or excessive resistance in the coolant temperature sensor circuit.

B. Remove the connector at the coolant temperature sensor and check for any corrosion. This may require a mirror to carefully inspect the connector on the temperature sensor depending on the vehicle type. Clean or replace as necessary.




C. Test the coolant temperature sensor with a OHM meter: