Refrigerant Pressure Sensor / Switch: Testing and Inspection
A/C Pressure Switch Circuit TroubleshootingNOTE:
- Do not use this troubleshooting procedure if any of the following items are operative; A/C condenser fan, radiator fan, A/C compressor. Refer to the symptom troubleshooting index. Symptom Related Diagnostic Procedures
- Before performing symptom troubleshooting, check for power train DTCs.
1. Check for body DTCs using B-CAN system diagnosis test mode A troubleshooting.
Are there any DTCs indicated?
YES - Do the appropriate troubleshooting for the DTC indicated.
NO - Go to step 2.
2. Disconnect the A/C pressure switch 4P connector.
3. Turn the ignition switch ON (II).
4. Measure the voltage between the No. 1 terminal of the A/C pressure switch 4P connector and body ground.
Is there 5 V or more?
YES - Go to step 5.
NO - Repair open in the wire between the relay control module and the A/C pressure switch.
5. Turn the ignition switch OFF.
6. Check for continuity between the No. 1 and No. 4 terminals of the A/C pressure switch.
Is there continuity?
YES - Go to step 7.
NO - Go to step 16.
7. Reconnect the A/C pressure switch 4P connector.
8. Disconnect climate control unit connector A (20P).
9. Turn the ignition switch ON (II).
10. Measure the voltage between the No. 14 terminal of climate control unit connector A (20P) and body ground.
Is there 5 V or more?
YES - Go to step 11.
NO - Repair open in the wire between the climate control unit and the A/C pressure switch.
11. Turn the ignition switch OFF.
12. Measure the evaporator sensor resistance between the No. 5 and No. 18 terminals of climate control unit connector A (20P).
Is the resistance less than 24 kOhms?
YES - Go to step 13.
NO - Repair cause of high resistance in the evaporator temperature circuit.
13. Reconnect climate control unit connector A (20P).
14. Turn the ignition switch ON (II).
15. Check that blower motor operates at all speeds.
Does the blower motor operate at all speeds?
YES - Check for loose wires or poor connections at climate control unit connector A (20P) and at the A/C pressure switch 4P 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.
NO - Repair the problem in the blower motor circuit.
16. Check for proper A/C system pressure.
Is the pressure within specifications?
YES - Replace the A/C pressure switch.
NO - Repair the A/C pressure problem.