DTC M

DTC indicator M: A Short in the Heater Core Temperature Sensor Circuit.

1. Disconnect the heater core temperature sensor 2P connector.
2. Test the heater core temperature sensor.

Is the resistance within the specifications shown on the graph?

YES - Go to step 3.

NO - Replace the heater core temperature sensor.

3. Disconnect heater control panel connector B (22P).




4. Check for continuity between the No. 4 terminal of heater control panel connector B (22P) and body ground.

Is there continuity?

YES - Repair short to body ground in the wire between the heater control panel and the heater core temperature sensor.

NO - Substitute a known-good heater control panel, and recheck. If the symptom/indication goes away, replace the original heater control panel.