B2979

DTC B2979 or DTC indicator B and WINDSHIELD DEFROST: An Open in the A/C Pressure Sensor Circuit

1. Clear the DTC with the HDS.
2. Turn the ignition switch OFF and then ON (II).
3. Do the self-diagnostic with the HDS or climate control unit.
4. Check for DTCs.

Is DTC B2979 or B and WINDSHIELD DEFROST 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 OFF.
6. Disconnect the A/C pressure sensor 3P connector.
7. Disconnect climate control unit connector A (40P).




8. Check for continuity between the following terminals of climate control unit connector A (40P) 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. Reconnect climate control unit connector A (40P).
10. Turn the ignition switch ON (II).




11. Measure the voltage between climate control unit connector A (40P) terminals No. 6 and No. 8, and between climate control unit connector A (40P) terminals No. 8 and No. 26.

Is there about 5 volts?

YES - Replace the A/C pressure sensor.

NO - Check for loose wires or poor connections at climate control unit connector A (40P) and at the A/C pressure sensor 3P connector. If the connections are good, substitute a known-good climate control unit, and recheck. If the symptom/ indication goes away, replace the original climate control unit.