Short in the A/C Pressure Sensor Circuit

DTC Troubleshooting: B2980 (6)

DTC B2980 or DTC indicator 6:

A short in the A/C Pressure Sensor 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 B2980 or 6 indicated?

YES -

Go to step 5.

NO -

Intermittent failure.�

5. Check for DTCs.

Are these DTCs also present; B1234 or 2, and/ or B1245 or 7?

YES -

Go to step 16.

NO -

Go to step 6.

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

7. Disconnect the A/C pressure sensor 3P connector.

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

9. Check for continuity between body ground and HVAC control unit connector A (24P) terminal No. 20.





Is there continuity?

YES -

Repair a short to body ground in the wire between the HVAC control unit and the A/C pressure sensor.�

NO -

Go to step 10.

10. Check for continuity between HVAC control unit connector A (24P) terminals No. 14 and No. 20.





Is there continuity?

YES -

Repair a short in the wire(s).�

NO -

Go to step 11.

11. Turn the ignition switch to ON (II), and measure the voltage between body ground and HVAC control unit connector A (24P) terminal No. 20.





Is there any voltage?

YES -

Repair a short to power in the wire between the HVAC control unit and the A/C pressure sensor. This short may also damage the HVAC control unit. Repair a short to power before replacing the HVAC control unit.�

NO -

Go to step 12.

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

13. Reconnect HVAC control unit connector A (24P).

14. Turn the ignition switch to ON (II).

15. Measure the voltage between HVAC control unit connector A (24P) terminals No. 4 and No. 14, and between HVAC control unit connector A (24P) terminals No. 4 and No. 20.





Is there about 5 V?

YES -

Replace the A/C pressure sensor.�

NO -

Check for loose wires or poor connections at HVAC control unit connector A (24P) and at the A/C pressure sensor 3P connector. If the connections are 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.�

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

17. Disconnect these items:

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

18. 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 19.

19. 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 20.

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

21. Reconnect HVAC control unit connector A (24P).

22. 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 23.

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.�

23. 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.�