Without Climate Control

DTC Troubleshooting: B2980 (5)

DTC B2980 or DTC indicator 5:

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 5 indicated?

YES -

Go to step 5.

NO -

Intermittent failure. Check for loose wires or poor connections on the A/C pressure sensor circuit.

5. Check for DTCs.

Is DTC B1234 or 2 also present?

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 the HVAC control unit 28P connector.

9. Check for continuity between HVAC control unit 28P connector terminal No. 23 and body ground.





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 28P connector terminals No. 23 and No. 25.





Is there continuity?

YES -

Repair short in the wires between the HVAC control unit and the A/C pressure sensor.

NO -

Go to step 11.

11. Turn the ignition switch to ON (II), and measure the voltage between HVAC control unit 28P connector terminal No. 23 and body ground.





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 the HVAC control unit 28P connector.

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

15. Measure the voltage between HVAC control unit 28P connector terminals No. 13 and No. 23, and between HVAC control unit 28P connector terminals No. 13 and No. 25.





Is there about 5 V?

YES -

Replace the A/C pressure sensor.

NO -

Check for loose wires or poor connections at the HVAC control unit 28P connector 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 (Without Climate Control).

16. Turn the ignition switch to LOCK (0), and disconnect the HVAC control unit 28P connector.

17. Disconnect these items:

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

18. Check for continuity between HVAC control unit 28P connector terminal No. 25 and body ground.





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 19.

19. Turn the ignition switch to ON (II), and measure the voltage between HVAC control unit 28P connector terminal No. 25 and 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 the HVAC control unit 28P connector.

22. Turn the ignition switch to ON (II), and measure the voltage between HVAC control unit 28P connector terminal No. 25 and body ground.





Is there about 5 V?

YES -

Go to step 23.

NO -

Check for loose wires or poor connections at the HVAC control unit 28P connector. 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 (Without Climate Control).

23. While measuring the voltage between HVAC control unit 28P connector terminal No. 25 and body ground, reconnect these items individually and note the voltage reading each time:

- Front 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 (Without Climate Control).

NO -

Replace the component that caused the voltage drop.