Diesel Data: Automotive Repair

With Climate Control




DTC Troubleshooting: B1228 (D)

DTC B1228 or DTC indicator D:

A Short in the Outside Air Temperature Sensor Circuit

1. Clear the DTC with the HDS.

2. Operate the climate control system in several modes.

3. Check for DTCs using the HDS or the self-diagnostic function.

Is DTC B1228 or D indicated?

YES -

Go to step 4.

NO -

Intermittent failure. Check for loose wires or poor connections on the outside air temperature sensor circuit.�

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

5. Remove the outside air temperature sensor Service and Repair, and test it Outside Air Temperature Sensor Test.

Is the outside air temperature sensor OK?

YES -

With the outside air sensor temperature disconnected go to step 6.

NO -

Replace the outside air temperature sensor Service and Repair.�

6. Disconnect the climate control unit 30P connector.

7. Check for continuity between body ground and climate control unit 30P connector terminal No. 9.





Is there continuity?

YES -

Repair a short to body ground in the wire between the climate control unit and the outside air temperature sensor.�

NO -

Go to step 8.

8. Check for continuity between climate control unit 30P connector terminals No. 9 and No. 22.





Is there continuity?

YES -

Repair a short in the wire(s) between the climate control unit and the outside air temperature sensor.�

NO -

Substitute a known-good climate control unit Climate Control Unit Removal/Installation, and recheck. If the symptom/indication goes away, replace the original climate control unit Climate Control Unit Removal/Installation.�