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; condenser fan, radiator fan, A/C compressor, or if the heater is inoperative. Refer to the symptom troubleshooting index. Heating/Air Conditioning
- Before performing symptom troubleshooting, check for powertrain DTCs.
1. Disconnect the A/C pressure switch 2P connector.
2. Turn the ignition switch ON (II).
3. Measure the voltage between the No. 2 terminal of the A/C pressure switch 2P connector and body ground.
Is there about 5 V?
YES - Go to step 4.
NO - Go to step 12.
4. Turn the ignition switch OFF.
5. Check for continuity between the No. 1 and No. 2 terminals of the A/C pressure switch.
Is there continuity?
YES - Go to step 6.
NO - Go to step 15.
6. Reconnect the A/C pressure switch 2P connector.
7. Disconnect the heater control panel 30P connector.
8. Turn the ignition switch ON (II).
9. Measure the voltage between the No. 23 terminal of the heater control panel 30P connector and body ground.
Is there about 5 V?
YES - Go to step 10.
NO - Repair open in the wire between the heater control panel and the A/C pressure switch.
10. Turn the ignition switch OFF.
11. Measure the resistance between the No. 19 and No. 27 terminals of the heater control panel 30P connector.
Is the resistance less than 24 KiloOhms?
YES - Check for loose wires or poor connections at the heater control panel 30P connector and at the A/C pressure switch 2P connector. If the connections are good, substitute a known-good heater control panel, and recheck. If the symptom/indication goes away, replace the original heater control panel.
NO - Repair cause of high resistance in the evaporator temperature circuit.
12. Turn the ignition switch OFF.
13. Disconnect the PCM connector A (44P).
14. Check for continuity between the No. 41 terminal of PCM connector A (44P) and No. 2 terminal of the A/C pressure switch 2P connector.
Is there continuity?
YES - Check for loose wires or poor connections at the PCM connector A (44P). If the connections are good, substitute a known-good PCM, and recheck. If the symptom/indication goes away, replace the original PCM, then perform the PCM idle learn procedure in Computers and Control Systems.
NO - Repair open in the wire between the PCM and the A/C pressure switch.
15. 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.