Diagnostic Aids

If this DTC is set, ECT sensor may be skewed. Compare coolant temperature on scan tool display with actual engine coolant temperature measured with a thermometer. If displayed engine coolant temperature is not close to actual engine coolant temperature, replace ECT sensor. Check for a poor PCM electrical connection. Check for proper operation of thermostat.

An intermittent malfunction may be caused by a poor connection, rubbed-through wire insulation, or a wire broken inside insulation. Check harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, or poor terminal-to-wire connections before component replacement.