Heating/Air Conditioning
DTC B1228 or DTC indicator 10: A Short in the Outside Air Temperature Sensor Circuit1. Clear the DTC with the HDS.
2. Operate the heater-A/C control system in several modes.
3. Check for DTCs using the HDS or self-diagnostic.
Is DTC B1228 or 10 indicated?
YES - Go to step 4.
NO - Intermittent failure.
4. Turn the ignition switch OFF.
5. Remove the outside air temperature sensor and test it.
Is the outside air temperature sensor OK?
YES - Go to step 6.
NO - Replace the outside air temperature sensor.
6. Disconnect the HVAC control unit 30P connector.
7. Check for continuity between body ground and the HVAC control unit 30P connector No. 8 and No. 20 terminals.
Is there continuity?
YES - Repair short to body ground in the wires between the HVAC control unit and the outside air temperature sensor.
NO - Go to step 8.
8. Check for continuity between the HVAC control unit 30P connector No. 8 and No. 20 terminals.
Is there continuity?
YES - Repair short in the wires between the HVAC control unit and the outside air temperature sensor.
NO - Substitute a known-good HVAC control unit, and recheck. If the symptom/indication goes away, replace the original HVAC control unit.