B2979

DTC Troubleshooting: B2979 (PRE sensor open)

DTC B2979 or PRE sensor open is indicated:

An Open in the A/C Pressure Sensor 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 with the HDS or the climate control unit.

4. Check for DTCs.

Is DTC B2979 or PRE sensor open indicated?

YES -

Go to step 5.

NO -

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

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

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

7. Disconnect the climate control unit 40P connector.

8. Check for continuity between the following terminals of the climate control unit 40P connector and the A/C pressure sensor 3P connector.









Is there continuity?

YES -

Go to step 9.

NO -

Repair an open in the wire(s) between the climate control unit and the A/C pressure sensor.�

9. Check for proper A/C system pressure.

Is the pressure within specifications?

YES -

Check for loose wires or poor connections at the climate control unit 40P connector and at the A/C pressure sensor 3P connector. If the connections are good, replace the A/C pressure sensor. If the symptom/indication continues, substitute a known-good climate control unit, and recheck. If the symptom/indication goes away, replace the original climate control unit Climate Control Unit Removal/Installation.�

NO -

Repair the A/C pressure problem.�