B1237

DTC Troubleshooting: B1237 (N and AUTO)

DTC B1237 or DTC indicator N and AUTO:

A Short in the Passenger's Air Mix Control Motor Circuit

1. Clear the DTC with the HDS.

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

3. Do the self-diagnostic function with the HDS or the climate control unit. Initial Inspection and Diagnostic Overview

4. Check for DTCs.

Is DTC B1237 or N and AUTO indicated?

YES -

Go to step 5.

NO -

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

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

6. Disconnect the passenger's air mix control motor 7P connector.

7. Disconnect the climate control unit 36P connector.

8. Check for continuity between body ground and climate control unit 36P connector terminals No. 13 and No. 20 individually.





Is there continuity?

YES -

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

NO -

Go to step 9.

9. Check for continuity between climate control unit 36P connector terminals No. 13 and No. 20.





Is there continuity?

YES -

Repair a short in the wires between the climate control unit and the passenger's air mix control motor.�

NO -

Go to step 10.

10. Turn the ignition switch to ON (II), and measure the voltage between body ground and climate control unit 36P connector terminals No. 13 and No. 20 individually.





Is there battery voltage?

YES -

Repair a short to power in the wire(s) between the climate control unit and the passenger's air mix control motor. This short may also damage the climate control unit. Repair the short to power before replacing the climate control unit Climate Control Unit Removal/Installation.�

NO -

Go to step 11.

11. Test the passenger's air mix control motor Passenger's Air Mix Control Motor Test (With Climate Control).

Is the passenger's air mix control motor OK?

YES -

Check the passenger's air mix control motor operation with the original climate control unit. If the motor operation is no good, substitute a known-good climate control unit, and recheck. If the symptom/indication goes away and the passenger's air mix control motor runs, replace the original climate control unit Climate Control Unit Removal/Installation.�

NO -

Replace the passenger's air mix control motor Passenger's Air Mix Control Motor Replacement (With Climate Control).