HVAC

DTC Troubleshooting: B1245 (7)

DTC B1245 or DTC indicator 7:

A Short in the Rear Air Mix Control Motor Circuit

1. Clear the DTCs 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 HVAC control unit.

4. Check for DTCs.

Is DTC B1245 or 7 indicated?

YES -

Go to step 5

NO -

Intermittent failure.�

5. Check for DTCs.

Are these DTCs also present; B1234 or 2, and/or B2980 or 6?

YES -

Go to step 13.

NO -

Go to step 6.

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

7. Test the rear air mix control motor .

Is the rear air mix control motor OK?

YES -

Go to step 8.

NO -

Replace the rear air mix control motor.�

8. Disconnect the rear air mix control motor 7P connector.

9. Disconnect HVAC control unit connector A (24P).

10. Check for continuity between HVAC control unit connector A (24P) terminal No. 15 and body ground.





Is there continuity?

YES -

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

NO -

Go to step 11.

11. Check for continuity between HVAC control unit connector A (24P) terminals No. 14 and No. 15.





Is there continuity?

YES -

Repair a short in the wire(s).�

NO -

Go to step 12.

12. Turn the ignition switch to ON (II), and measure the voltage between HVAC control unit connector A (24P) terminal No. 15 and body ground.





Is there any voltage?

YES -

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

NO -

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

13. Turn the ignition switch to LOCK (0), and disconnect HVAC control unit connector A (24P).

14. Disconnect these items:

- Front air mix control motor
- Rear air mix control motor
- A/C pressure sensor

15. Check for continuity between HVAC control unit connector A (24P) terminal No. 14 and body ground.





Is there continuity?

YES -

Repair a short to body ground in the wire.�

NO -

Go to step 16.

16. Turn the ignition switch to ON (II), and check the same terminal for voltage to body ground.





Is there any voltage?

YES -

Repair a short to power in the wire. This short may have also damaged the HVAC control unit. Repair a short to power before replacing the HVAC control unit.�

NO -

Go to step 17.

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

18. Reconnect the HVAC control unit connector A (24P).

19. Turn the ignition switch to ON (II), and measure the voltage between HVAC control unit connector A (24P) terminal No. 14 and body ground.





Is there about 5 V?

YES -

Go to step 20

NO -

Check for a loose wire or poor connection at HVAC control unit connector A (24P). If the connection is good, substitute a known-good HVAC control unit and recheck. If the symptom/indication goes away, replace the original HVAC control unit HVAC Control Unit Removal/Installation.�

20. While checking the same terminal for voltage to ground, reconnect these items individually and note the voltage reading each time:

- Front air mix control motor
- Rear air mix control motor
- A/C pressure sensor





Does the voltage remain at about 5 V?

YES -

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

NO -

Replace the component that caused the voltage drop.�