Honda Accord: A/C Pressure Switch Circuit Troubleshooting

NOTE: • Do not use this troubleshooting procedure if any of the following items are operative: The condenser fan, the radiator fan, or the A/C compressor, or if the heater is inoperative. Refer to the symptom troubleshooting index.

• Check the A/C high-side pressure.

• Before doing any symptom troubleshooting, check for powertrain DTCs (see page 11-3). Also check for B-CAN codes (see page 22-134).

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

2. Check if the blower motor operates at all speeds.

Does the blower motor operate at all speeds? YES

-Go to step 3.

NO

-Repair the problem in the blower motor circuit (see page 21-38).

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

4. Disconnect the HVAC control unit 24P connector.

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

6. Measure the voltage between HVAC control unit 24P connector terminal No. 21 and body ground.

HVAC CONTROL UNIT 24P CONNECTOR

Wire side of female terminals

Is there battery voltage? YES

-Go to step 14.

NO

-Go to step 7.

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

8. Disconnect the A/C pressure switch 2P connector.

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

10. Measure the voltage between A/C pressure switch 2P connector No. 2 and body ground,

A/C PRESSURE SWITCH 2P CONNECTOR

Wire side of female terminals

Is there battery voltage? YES

-Go to step 11.

NO

-Repair an open in the wire between the A/C pressure switch and the MICU. If the wire is OK, substitute a known-good MICU and recheck. If the symptom goes away, replace the original MICU.

11. Check for continuity between terminals No. 1 and No. 2 of A/C pressure switch.

A/C PRESSURE SWITCH

Is there continuity? YES

-Go to step 12.

NO-

Replace the A/C pressure switch.

12. Connect A/C pressure switch 2P connectorterminal No. 2 to body ground with a jumper wire.

A /C PRESSURE SWITCH 2P CONNECTOR

Wire side of female terminals

Do the compressor and fans operate? YES

-Go to step 13.

NO

-Check for B-CAN codes (see page 22-134).

13. Check for continuity between HVAC control unit 24P connectorterminal No. 21 and A/C pressure switch 2P connectorterminal No. 1.

HVAC CONTROL UNIT 24P CONNECTOR

Wire side of female terminals

A /C PRESSURE SWITCH 2P CONNECTOR

Wire side of female terminals

Is there continuity? YES

-Check for loose wires or poor connections at the HVAC control unit 24P connector and at the A/C pressure switch 2P connector.

NO

-Repair an open in the wire between the HVAC control unit and A/C pressure switch.

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

15. Measure the evaporator temperature sensor resistance between HVAC control unit 24P connector terminal No. 14 and No. 15.

HVAC CONTROL UNIT 24P CONNECTOR

Wire side of female terminals

Is resistance less than 24 kO? YES-

Check for loose wires or poor connections at the HVAC control unit 24P connector. If the connections are good, substitute a known-good HVAC control unit and recheck. If the symptom goes away, replace the original HVAC control unit (see page 21-65).

NO

-Test the evaporator temperature sensor (see page21~58).