Pinpoint Test D: The Air Conditioner (A/C) Is Always On
- D1 RETRIEVE AND RECORD THE DTCS FROM THE CONTINUOUS AND ON DEMAND SELF-TEST-PCM
- Connect the scan tool.
- Make sure the function selector switch is in the OFF position.
- Key in ON position.
- Enter the following diagnostic mode on the scan tool: PCM Self-Test.
- Retrieve and document the continuous DTCs.
- Is DTC P1464 retrieved?
Yes: GO to D2.
No: GO to D7.
- D2 CHECK THE A/C CYCLING SWITCH PID WITH THE A/C OFF
- Enter the following diagnostic mode on the scan tool: PCM PIDs.
- Turn the function selector switch to the OFF position.
- Monitor the PCM A/C cycling switch PID.
- Does the PCM A/C cycling switch PID read ON?
Yes: GO to D3.
No: GO to D7.
- D3 CHECK FOR A FALSE INPUT SIGNAL TO THE PCM
- Key in OFF position.
- Disconnect: PCM C175b.
- Key in ON position.
- Turn the function selector switch to the OFF position.
- Measure the voltage between PCM C175b-15, circuit 198 (DG/OG), harness side and ground.
- Is the voltage greater than 10 volts?
Yes: GO to D4.
No: GO to D6.
- D4 CHECK THE FUNCTION SELECTOR SWITCH FOR A SHORT TO POWER
- Key in OFF position.
- Disconnect: Function Selector Switch C294a.
- Key in ON position.
- Enter the following diagnostic mode on the scan tool: PCM PIDs.
- Does the PCM A/C cycling switch PID read ON?
Yes: GO to D5.
No: INSTALL a new function selector switch. REFER to REMOVAL AND INSTALLATION . TEST the system for normal operation.
- D5 CHECK CIRCUIT 348 (VT) FOR A SHORT TO POWER
- Key in OFF position.
- Disconnect: A/C Cycling Switch C130.
- Key in ON position.
- Enter the following diagnostic mode on the scan tool: PCM PIDs.
- Does the PCM A/C cycling switch PID read ON?
Yes: GO to D6.
No: REPAIR the circuit. TEST the system for normal operation.
- D6 CHECK CIRCUIT 198 (DG/OG) FOR A SHORT TO POWER
- Key in OFF position.
- Disconnect: Dual Pressure Switch C1062.
- Key in ON position.
- Enter the following diagnostic mode on the scan tool: PCM PIDs.
- Does the PCM A/C cycling switch PID read ON?
Yes: REPAIR circuit 198 (DG/OG). TEST the system for normal operation.
No: REPAIR circuit 441 (RD/YE). TEST the system for normal operation.
- D7 CHECK FOR A SHORTED A/C CLUTCH RELAY
- Disconnect: A/C Clutch Relay C1008.
- Start the vehicle.
- Observe the A/C compressor.
- Is the A/C compressor clutch engaged?
Yes: CONNECT the A/C relay. GO to D11.
No: GO to D8.
- D8 CHECK A/C CLUTCH RELAY
- Carry out the A/C clutch relay component test. Refer to COMPONENT TESTING for component testing.
- Is the A/C clutch relay OK?
Yes: GO to D9.
No: INSTALL a new A/C clutch relay. TEST the system for normal operation.
- D9 CHECK CIRCUIT 331 (PK/YE) FOR A SHORT TO GROUND
- Key in OFF position.
- Disconnect: PCM C175b.
- Measure the resistance between A/C clutch relay C1008-2, circuit 331 (PK/YE), harness side and ground.
- Is the resistance less than 5 ohms?
Yes: REPAIR the circuit. TEST the system for normal operation.
No: GO to D10.
- D10 CHECK FOR CORRECT PCM OPERATION
- Disconnect all PCM connectors.
- Check for:
- corrosion.
- pushed-out pins.
- Connect all PCM connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes: INSTALL a new PCM. REFER to INSTALLATION - 2.3L or INSTALLATION - 3.0L . TEST the system for normal operation.
No: The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.
- D11 CHECK CIRCUIT 321 (GY/WH) FOR A SHORT TO POWER
- Key in OFF position.
- Disconnect: A/C Clutch Field Coil C100.
- Key in ON position.
- Measure the voltage between A/C clutch field coil CJ100-1, circuit 321 (GY/WH), harness side and ground.
- Is the voltage greater than 10 volts?
Yes: REPAIR the circuit. TEST the system for normal operation.
No: CHECK the clutch air gap. REFER to AIR CONDITIONING (A/C) CLUTCH AIR GAP ADJUSTMENT .