Pinpoint Test P: The Air Conditioning (A/C) Is Always On
WARNING: This page is about a different car, the 2010 Mercury Mariner and 2010 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Diagnose any PCM, HVAC module or ACCM
DTCs before carrying out the following pinpoint test.
- P1 CHECK THE A/C EVAPORATOR TEMPERATURE (EVAP_TEMP) HVAC PID
- Allow the vehicle exterior and interior to stabilize to an ambient temperature.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: EVAP_TEMP HVAC PID.
- Does the EVAP_TEMP HVAC PID read similar to the ambient temperature?
- Yes: GO to P2 .
- No: INSTALL a new A/C evaporator discharge temperature sensor. TEST the system for normal operation.
- P2 CHECK THE (A/C) SWITCH (CC_SW_AC) HVAC PID WITH THE A/C OFF
- Start the engine.
- Enter the following diagnostic mode on the scan tool: CC_SW_AC HVAC PID.
- Select PANEL and make sure the A/C indicator is OFF.
- Does the CC_SW_AC HVAC PID read Inactive?
- Yes: GO to P3 .
- No: INSTALL a new HVAC module. REFER to HEATING VENTILATION AIR CONDITIONING (HVAC) MODULE . TEST the system for normal operation.
- P3 CHECK THE AIR CONDITIONING COMPRESSOR COMMANDED STATE (ACC_CMD) PCM PID WITH THE A/C OFF
- Enter the following diagnostic mode on the scan tool: ACC_CMD PCM PID.
- Select PANEL and make sure the A/C indicator is OFF.
- Does the ACC_CMD PCM PID read OFF?
- Yes: INSTALL a new electric A/C compressor. REFER to REMOVAL AND INSTALLATION . TEST the system for normal operation.
- No: INSTALL a new PCM. TEST the system for normal operation.