DTC B2979 or DTC indicator L and AUTO: An Open in the A/C Pressure Sensor Circuit
- Clear the DTCs with the HDS.
- Turn the ignition switch to LOCK (0), and then back to ON (II).
- Do the Self-Diagnostic Function with the HDS (see HOW TO USE THE SELF-DIAGNOSTIC FUNCTION WITH THE HDS ) or the climate control unit (see HOW TO USE THE CLIMATE CONTROL UNIT SELF-DIAGNOSTIC FUNCTION WITHOUT THE HDS ).
- Check for DTCs.
Is DTC B2979 or L and AUTO indicated?
YES -Go to step 5.
NO -Intermittent failure. Check for loose wires or poor connections on the A/C pressure sensor circuit.
- Turn the ignition switch to LOCK (0).
- Disconnect the A/C pressure sensor 3P connector.
- Disconnect climate control unit connector A (28P).
- Check for continuity between the following terminals of climate control unit connector A (28P) and the A/C pressure sensor 3P connector.CONTINUITY REFERENCE
28P: 3P: No. 13 No. 1 No. 23 No. 2 No. 25 No. 3 Fig 1: Checking Continuity Between Terminals Of Climate Control Unit And A/C Pressure Sensor ConnectorCourtesy of AMERICAN HONDA MOTOR CO., INC.
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.
- Reconnect climate control unit connector A (28P).
- Turn the ignition switch to ON (II).
- Measure the voltage between climate control unit connector A (28P) terminal No. 13 and No. 23, and climate control unit connector A (28P) terminal No. 13 and No. 25.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there about 5 V?
YES -Replace the A/C pressure sensor.
NO -Check for loose wires or poor connections at climate control unit connector A (28P) 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 (see CLIMATE CONTROL UNIT REMOVAL/INSTALLATION ).