Honda Accord: A/C Pressure Switch Circuit
Troubleshooting - Climate Control - Heating, Ventilation, and Air Conditioning - Honda Accord MK8 2008-2012 Service ManualHonda Accord: A/C Pressure Switch Circuit Troubleshooting

NOTE: • if the blower motor does not run at all speeds, the A/C compressor will be inoperative. Run the self-diagnostic function, and check for DTC B1241.

Before performing any other troubleshooting, repair the cause of the inoperative blower motor.

• 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 symptom troubleshooting, check for powertrain DTCs (see page 11-3). Also check for B-CAN codes (see page 22-109).

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 page21-166).

3. Do the sensor input display mode (see page 21-107).

Is Sensor #5 (evaporative outlet air temperature) above 3В°C? YES

-Go to step 4.

NO-

Go to step 15.

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

5. Disconnect climate control unit connector A (28P).

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

7. Measure the voltage between climate control unit connector A (28P) terminal No. 21 and body ground.

CLIMATE CONTROL UNIT CONNECTOR A (28P)

Wire side of female terminals


Wire side of female terminals

*1: With navigation

*2: Without navigation

Is there battery voltage? YES

-Replace the climate control unit (with navigation) (see page 21-190), (without navigation) (see page 21-191 ) . NO

-Go to step 8.

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

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

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

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

A /C PRESSURE SWITCH 2P CONNECTOR

Wire side of female terminals


Wire side of female terminals

Is there battery voltage? YES-

Go to step 12.

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.

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

A/C PRESSURE SWITCH

Is there continuity?


Is there continuity? Y E S

- G o to step 13.

NO

-Replace the A/C pressure switch.

13. Connect A/C pressure switch 2P connector terminal No. 2 to body ground with a jumper wire.

A/C PRESSURE SWITCH 2P CONNECTOR

Wire side of female terminals


Wire side of female terminals

Do the compressor and fans operate? YES

-Go to step 14.

NO

-Check for B-CAN codes (see page 22-109).

14. Check for continuity between climate control unit connector A (28P) terminal No. 21 and A/C pressure switch 2P connector terminal No. 1.

CLIMATE CONTROL UNIT CONNECTOR A (28P)

Wire side of female terminals

A /C PRESSURE SWITCH 2P CONNECTOR


A /C PRESSURE SWITCH 2P CONNECTOR

Wire side of female terminals

*1: With navigation

*2: Without navigation

Is there continuity? YES

-Check for loose wires or poor connections at the climate control unit connector A (28P) 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.

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

16. Disconnect climate control unit connector A (28P) and B(12P).

17. Measure the evaporator temperature sensor resistance between climate control u n i t connector A (28P) terminal No. 23 and connector B (12P) terminal No. 10.

CLIMATE CONTROL UNIT CONNECTOR A (28P)

Wire side of female terminals

CLIMATE CONTROL UNIT CONNECTOR B (12P)


CLIMATE CONTROL UNIT CONNECTOR B (12P)

Wire side of female terminals

* 1 : With navigation

*2: Without navigation

Is the resistance less than 24 kO? YES

-Check for loose wires or poor connections at the climate control unit connectors. If the connections are good, substitute a known-good climate control unit and recheck. if the symptom goes away, replace the original climate control unit (with navigation) (see page 21-190), (without navigation) (see page 21-191 ) . NO

-Test the evaporator temperature sensor (see page 21-58).

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