Without Climate Control

DTC Troubleshooting: B1234 (2)

DTC B1234 or DTC indicator 2:

A Short in the Air Mix Control Motor Circuit

1. 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 the self-diagnostic function.

Is DTC B1234 or 2 indicated?

YES -

Go to step 4.

NO -

Intermittent failure. Check for loose wires or poor connections on the air mix control motor circuit.�

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

5. Disconnect the air mix control motor 7P connector.

6. Disconnect the HVAC control unit 30P connector.

7. Check for continuity between body ground and HVAC control unit 30P connector terminals No. 22 and No. 23 individually.





Is there continuity?

YES -

Repair a short to body ground in the wire(s) between the HVAC control unit and the air mix control motor.�

NO -

Go to step 9.

8. Check for continuity between HVAC control unit 30P connector terminals No. 22 and No. 23.





Is there continuity between the terminals?

YES -

Repair the short in the wires between the HVAC control unit and the air mix control motor.�

NO -

Go to step 9.

9. Turn the ignition switch to ON (II), and check the same terminals for voltage between each terminal and body ground.





Is there voltage?

YES -

Repair a short to power in the wire(s) between the HVAC control unit and the air mix control motor. This short may also damage the HVAC control unit. Repair the short to power before replacing the HVAC control unit.�

NO -

Go to step 10.

10. Test the air mix control motor Air Mix Control Motor Test (Without Climate Control).

Is the air mix control motor OK?

YES -

Substitute a known-good HVAC control unit HVAC Control Unit Removal/Installation (Without Climate Control), and recheck. If the symptom/indication goes away, replace the original HVAC control unit HVAC Control Unit Removal/Installation (Without Climate Control).�

NO -

Replace the air mix control motor Air Mix Control Motor Replacement (Without Climate Control).