HVAC - Without Climate Control

HVAC DTC Troubleshooting: 15

DTC indicator 15: A Short in the Evaporator Temperature Sensor Circuit

1. Turn the ignition switch to LOCK (0), and then to ON (II).

2. Do the self-diagnostic function with the HVAC control unit. How to Troubleshoot the Heating and A/C Systems

3. Check for DTCs.

Is DTC 15 indicated?
YES - Go to step 4.

NO - Intermittent failure. Check for damaged wires or connections in the evaporator temperature sensor circuit.


4. Turn the ignition switch to LOCK (0).

5. Remove the evaporator temperature sensor Service and Repair and test it. Evaporator Temperature Sensor Test

Is the evaporator temperature sensor OK?
YES - Go to step 6.

NO - Replace the evaporator temperature sensor. Service and Repair


6. Disconnect the HVAC control unit 24P connector.

7. Check for continuity between body ground and the HVAC control unit 24P connector No. 14 terminal.

Is there continuity?
YES - Repair short to body ground in the wire between the HVAC control unit and the evaporator temperature sensor.

NO - Go to step 8.






8. Check for continuity between the HVAC control unit 24P connector No. 14 and No. 15 terminals.

Is there continuity?
YES - Repair short in the wires between the HVAC control unit and the evaporator temperature sensor.

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