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Home >> Ford >> 2000 >> Taurus LX, 3.0 2, AX4N >> Repair and Diagnosis >> External Pages >> Different car >> Section 1475 (HVAC - Climate Control System - General Information And Diagnostics - (Hybrid)) >> Diagnosis And Testing >> Climate Control System >> Pinpoint Tests >> Pinpoint Test O: The Air Conditioning (A/C) is Inoperative >> Pinpoint Test O: The Air Conditioning (A/C) Is Inoperative

Pinpoint Test O: The Air Conditioning (A/C) Is Inoperative

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.
NOTE: Before carrying out the following test, check that the A/C system pressure is above 290 kPa (42 psi). If the pressure is below 290 kPa (42 psi), refer to INSPECTION AND VERIFICATION .
  1. O1 CHECK THE A/C PRESSURE SENSOR (ACP_PRESS) PCM PID 
    • Ignition ON.
    • Enter the following diagnostic mode on the scan tool: ACP_PRESS PCM PID.
    • With the manifold gauge set connected, compare the pressure readings of the manifold gauge set and the ACP_PRESS PID.
    • Are the pressure values of the manifold gauge set and the ACP_PRESS PID similar? 
    • Yes:  GO to O2  .
    • No:  INSTALL a new A/C pressure transducer. TEST the system for normal operation.
  2. O2 CHECK THE A/C EVAPORATOR TEMPERATURE (EVAP_TEMP) HVAC PID 
    • Allow the vehicle exterior and interior to stabilize to an ambient temperature.
    • 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 O3  .
    • No:  INSTALL a new A/C evaporator discharge temperature sensor. TEST the system for normal operation.
  3. O3 CHECK THE (A/C) SWITCH (CC_SW_AC) HVAC PID WITH THE A/C ON 
    • Start the engine.
    • Enter the following diagnostic mode on the scan tool: CC_SW_AC HVAC PID.
    • Select PANEL and press the A/C button (indicator OFF).
    • Does the CC_SW_AC HVAC PID read Active? 
    • Yes:  GO to O4  .
    • No:  GO to  O8.
  4. O4 CHECK THE AIR CONDITIONING COMPRESSOR COMMANDED STATE (ACC_CMD) PCM PID WITH THE A/C ON 
    • Enter the following diagnostic mode on the scan tool: ACC_CMD PCM PID.
    • Does the ACC_CMD PCM PID read ON? 
    • Yes:  GO to  O10.
    • No:  GO to O5  .
  5. O5 CHECK CIRCUIT CBK03 (GY) FOR VOLTAGE 
    • Ignition OFF.
    • Disconnect: Low Charge Protection Switch C130.
    • Ignition ON.
    • Measure the voltage between ground and low charge protection switch C130-2, circuit CBK03 (GY), harness side.
      Fig 1: Measuring Voltage Between Ground And Low Charge Protection Switch C130-2, Circuit CBK03 (GY) Harness Side
      G06394473Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts? 
    • Yes:  GO to O6  .
    • No:  VERIFY BJB  fuse 27 (10A) is OK. If OK, REPAIR circuit CBK03 (GY) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
  6. O6 CHECK THE LOW CHARGE PROTECTION SWITCH 
    • Ignition OFF.
    • Measure the resistance across the low charge protection switch terminals, component side.
    • Is the resistance less than 5 ohms? 
    • Yes:  GO to O7  .
    • No:  INSTALL a new low charge protection switch. TEST the system for normal operation.
  7. O7 CHECK CIRCUIT CH422 (VT) FOR AN OPEN 
    • Disconnect: PCM C175B.
    • Measure the resistance between PCM C175B-35, circuit CH422 (VT), harness side and low charge protection switch C130-1, circuit CH422 (VT), harness side.
      Fig 2: Checking Circuit CH422 (VT) For An Open
      G06394474Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
    • Yes:  GO to  O9.
    • No:  REPAIR circuit CH422 (VT) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
  8. O8 CHECK THE MODULE CONNECTION 
    • Inspect the module connectors for:
      • corrosion.
      • pushed-out terminals.
      • damaged terminals.
    • Connect and correctly seat all the HVAC module connectors.
    • Clear the DTCs.
    • Operate the system and verify the concern is still present.
    • Is the concern still present? 
    • Yes:  INSTALL a new HVAC module. REFER to HEATING VENTILATION AIR CONDITIONING (HVAC) MODULE . 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.
  9. O9 CHECK THE PCM CONNECTION 
    • Clear the DTCs.
    • Disconnect all of the PCM connectors.
    • Check for:
      • corrosion.
      • pushed-out terminals.
      • damaged terminals.
    • Connect and correctly seat all of the PCM connectors.
    • Operate the system.
    • Does the concern return? 
    • Yes:  INSTALL a new PCM. 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.
  10. O10 CHECK ACCM OPERATING CONDITIONS 
    • Make sure the following conditions are met:
      • The PCM does not detect excessively high or low refrigerant pressure from the A/C pressure transducer.
      • The PCM does not detect excessively high engine coolant temperature.
      • The PCM does not detect an ambient air temperature below -1°C (30°F).
      • The PCM has not detected a Wide Open Throttle (WOT) condition.
      • The HVAC module does not detect an evaporator discharge air temperature below 2°C (36°F).
    • Start the engine.
    • Select PANEL and press the A/C button (indicator on).
    • Does the A/C operate? 
    • Yes:  The system is operating correctly at this time. The concern may have been caused by attempting to operate the A/C outside of operating conditions.
    • No:  INSTALL a new electric A/C compressor. REFER to REMOVAL AND INSTALLATION . TEST the system for normal operation.
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