PRE Sensor Open Is Indicated

DTC Troubleshooting: B2979 or PRE sensor open is indicated

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 to ON (II).

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

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 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.

NO - Repair the A/C pressure problem.