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Pinpoint Test K: The Air Conditioning (A/C) Is Always On

NOTE: When disconnecting and reconnecting the pressure transducer electrical connector, make sure that the connector-locking device is in place and that the locking device and connector are correctly and fully seated.
  1. K1 CHECK THE A/C PRESSURE SENSOR (ACP_PSI) PCM PID 
    • Key in ON position.
    • Enter the following diagnostic mode on the diagnostic tool: A/C Pressure PCM PID
    • With the manifold gauge set connected, compare the pressure readings of the manifold gauge set and the ACP_PSI PID.
    • Are the pressure values of the manifold gauge set and the ACP_PSI PID similar? 
    1. YES  : Go to  K2.
    2. NO  : INSTALL a new A/C pressure transducer. TEST the system for normal operation.
  2. K2 CHECK THE POST EVAPORATOR TEMPERATURE SENSOR INPUT (PEVAP_TMP) PID 
    • Allow the vehicle exterior and interior to stabilize to an ambient temperature above 16°C (60°F).
    • Enter the following diagnostic mode on the diagnostic tool: PEVAP_TMP EATC PID
    • Does the PEVAP_TMP PID read similar to the ambient temperature? 
    1. YES  : Go to  K3.
    2. NO  : CARRY OUT the Temperature Sensor - Evaporator Discharge . If the sensor tests OK, go to  K11. If the sensor does not test OK, INSTALL a new heater core and evaporator core housing. REFER to CLIMATE CONTROL . CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
  3. K3 CHECK THE AIR CONDITIONING COMPRESSOR CYCLING SWITCH (ACCS) PID WITH THE A/C OFF 
    • Enter the following diagnostic mode on the diagnostic tool: ACCS PCM PID
    • Does the ACCS PCM PID read ON? 
    1. YES  : EATC, go to  K4.

      EMTC, go to  K5.

    2. NO  : Go to  K7.
  4. K4 CHECK THE AIR CONDITIONING SWITCH STATUS (CC_AC) PID WITH THE A/C OFF 
    • Enter the following diagnostic mode on the diagnostic tool: CC_AC PCM PID
    • Does the CC_AC PCM PID read ON? 
    1. YES  : Go to  K10.
    2. NO  : Go to  K11.
  5. K5 CHECK EMTC A/C REQUEST OUTPUT 
    • Key in OFF position.
    • Disconnect: Instrument Cluster (IC) C220
    • Key in ON position.
    • Select the OFF position on the EMTC module.
      • Fig 1: Measuring Resistance Between IC C220-23, Circuit CH434 (GY/YE) & Ground
      GF0030268Courtesy of FORD MOTOR CO.
    • Measure the resistance between IC C220-23, circuit CH434 (GY/YE) and ground.
    • Is the resistance less than 5 ohms? 
    1. YES  : Go to  K6.
    2. NO  : Go to  K11.
  6. K6 CHECK CIRCUIT CH434 (GY/YE) FOR A SHORT TO GROUND 
    • Key in OFF position.
    • Disconnect: EMTC C2357a
      • Fig 2: Measuring Resistance Between IC C220-23, Circuit CH434 (GY/YE) & Ground
      GF0030268Courtesy of FORD MOTOR CO.
    • Measure the resistance between IC C220-23, circuit CH434 (GY/YE) and ground.
    • Is the resistance greater than 10,000 ohms? 
    1. YES  : Go to  K10.
    2. NO  : REPAIR circuit CH434 (GY/YE) for a short to ground. TEST the system for normal operation.
  7. K7 CHECK THE AIR CONDITIONING CLUTCH (WAC_ACCR) PID WITH THE A/C OFF 
    • Enter the following diagnostic mode on the diagnostic tool: WAC_ACCR PCM PID
    • Does the WAC_ACCR PCM PID read ON? 
    1. YES  : REFER to Introduction - Gasoline Engines .
    2. NO  : Go to  K8.
  8. K8 CHECK FOR VOLTAGE TO THE A/C COMPRESSOR CLUTCH FIELD COIL 
    • Key in OFF position.
    • Disconnect: A/C Compressor Clutch Field Coil C100
    • Key in ON position.
    • Select the OFF position on the EMTC module.
      • Fig 3: Measuring Voltage Between A/C Compressor Clutch Field Coil C100-1, Circuit CH401 (VT/WH) & Ground
      GF0032117Courtesy of FORD MOTOR CO.
    • Measure the voltage between A/C compressor clutch field coil C100-1, circuit CH401 (VT/WH) and ground.
    • Is the voltage greater than 10 volts? 
    1. YES  : Go to  K9.
    2. NO  : INSTALL a new A/C compressor. REFER to CLIMATE CONTROL . TEST the system for normal operation.
  9. K9 CHECK CIRCUIT CH401 (VT/WH) FOR A SHORT TO VOLTAGE 
    • Key in OFF position.
    • Disconnect: A/C Clutch Relay
    • Key in ON position.
      • Fig 4: Measuring Voltage Between A/C Compressor Clutch Field Coil C100-1, Circuit CH401 (VT/WH) & Ground
      GF0032117Courtesy of FORD MOTOR CO.
    • Measure the voltage between A/C compressor clutch field coil C100-1, circuit CH401 (VT/WH) and ground.
    • Is the voltage greater than 10 volts? 
    1. YES  : REPAIR circuit CH401 (VT/WH) for a short to voltage. TEST the system for normal operation.
    2. NO  : INSTALL a new A/C clutch relay. Check the A/C clutch diode. INSTALL a new diode if necessary. TEST the system for normal operation.
  10. K10 CHECK THE MODULE CONNECTION 
    • Carry out the Electronic Automatic Temperature Control (EATC) Module and Electronic Manual Temperature Control (EMTC) Module Cold Boot Process.
      • NOTE: EATC systems only.
    • Carry out the EATC On-Demand Self Test.
    • Operate the system.
    • Does the concern return? 
    1. YES  : INSTALL a new EATC/EMTC module. REFER to CLIMATE CONTROL . TEST the system for normal operation.
    2. 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. TEST the system for normal operation.
  11. K11 CHECK THE PCM MODULE CONNECTION 
    • Clear the DTCs.
    • Disconnect all the PCM connectors.
    • Check for:
      • corrosion.
      • pushed-out pins.
      • incorrectly seated connector.
    • Connect and correctly seat all the PCM connectors.
    • Operate the system.
    • Does the concern return? 
    1. YES  : INSTALL a new PCM. TEST the system for normal operation.
    2. NO  : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
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