DTC 12: An Open in the Evaporator Temperature Sensor Circuit
- 1. Problem verification:
1. Turn the vehicle to the OFF (LOCK) mode and then the ON mode.
2. Do the Self-Diagnostic Function with the HVAC control unit .
3. Check for DTCs.
Is DTC 12 indicated?
YES
Go to step 2.
NO
Intermittent failure. Check for loose wires or poor connections on the evaporator temperature sensor circuit.
- 2. Open wire check (TEVA line):
1. Turn the vehicle to the OFF (LOCK) mode.
2. Disconnect the following connectors.
HVAC control unit 32P connector Evaporator temperature sensor 2P connector 3. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode HVAC control unit 32P connector: disconnected Evaporator temperature sensor 2P connector: disconnected Test point 1 HVAC control unit 32P connector No. 19 Test point 2 Evaporator temperature sensor 2P connector No. 1 Is there continuity?
YES
The TEVA wire is not open. Go to step 3.
NO
Repair an open in the wire between the HVAC control unit and the evaporator temperature sensor.
- 3. Open wire check (SENSOR COM/SENS-COM line):
1. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode HVAC control unit 32P connector: disconnected Evaporator temperature sensor 2P connector: disconnected Test point 1 HVAC control unit 32P connector No. 20 Test point 2 Evaporator temperature sensor 2P connector No. 2 Is there continuity?
YES
The SENSOR COM/SENS-COM wire is not open. Go to step 4.
NO
Repair an open in the wire between the HVAC control unit and the evaporator temperature sensor.
- 4. Shorted wire check (TEVA line to SENSOR 5V/S5V line):
1. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode HVAC control unit 32P connector: disconnected Evaporator temperature sensor 2P connector: disconnected Test point 1 HVAC control unit 32P connector No. 17 Test point 2 HVAC control unit 32P connector No. 19 Is there continuity?
YES
Repair a short in the wires between the HVAC control unit and the evaporator temperature sensor.
NO
The TEVA wire and SENSOR 5V/S5V wire are OK. Go to step 5.
- 5. Evaporator temperature sensor check:
1. Test the evaporator temperature sensor .
Is the evaporator temperature sensor OK?
YES
Replace the HVAC control unit .
NO
