LEMON Manuals: Even more car manuals for everyone
Home >> Mercury >> 2008 >> Milan Base, 2.3 Z, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 1354 (HVAC Climate Control System - General Information And Diagnostics) >> Diagnostic Tests >> Climate Control System >> Pinpoint Tests >> Pinpoint Test M: The Air Conditioning (A/C) is Inoperative >> Pinpoint Test M: The Air Conditioning (A/C) Is Inoperative

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

WARNING: This page is about a different car, the 2009 Mercury Milan, 2009 Lincoln MKZ, and 2009 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: It is important to install relays in their correct position in the Battery Junction Box (BJB). Installing a relay incorrectly may cause wiring shorts or damage to modules. While carrying out diagnostics on BJB relays, have only one BJB relay removed at a time. Failure to follow these instructions may result in damage to the vehicle circuitry or to control modules.
NOTE: Some PCM DTCs may inhibit A/C operation. If any PCM DTCs are retrieved, diagnose those first. Refer to Introduction - Gasoline Engines article.
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.
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 Fluorescent Dye Leak Detection .
  1. M1 CHECK THE A/C PRESSURE SENSOR (ACP_PRESS) PCM PID 
    • Key in ON position.
    • Enter the following diagnostic mode on the diagnostic tool: ACP_PRESS PCM PID
    • With the R-134a Manifold Gauge Set connected, compare the pressure readings of the R-134a Manifold Gauge Set and the ACP_PRESS PCM PID.
    • Are the pressure values of the R-134a Manifold Gauge Set and the ACP_PRESS PCM PID similar? 
    1. YES  : Go to  M2.
    2. NO  : INSTALL a new A/C pressure transducer. TEST the system for normal operation.
  2. M2 CHECK THE A/C EVAPORATOR TEMPERATURE (EVAP_TEMP) HVAC PID (3.5L ONLY) OR EVAPORATOR TEMPERATURE (A/CT) PCM 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: EVAP_TEMP HVAC PID (3.5L only) or A/CT PCM PID
    • Does the EVAP_TEMP HVAC PID (3.5L ONLY) or A/CT PCM PID read similar to the ambient temperature? 
    1. YES  : DATC/EATC, go to  M3.

      EMTC, go to  M4.

    2. NO  : INSTALL a new A/C evaporator discharge temperature sensor. TEST the system for normal operation.
  3. M3 CHECK THE AIR CONDITIONING SWITCH STATUS (CC_AC) HVAC PID WITH THE A/C ON 
    • Enter the following diagnostic mode on the diagnostic tool: CC_AC HVAC PID
    • Press and hold the A/C manual override button on the HVAC module - DATC or HVAC module - EATC module.
    • Does the CC_AC HVAC PID read DEPRESSED? 
    1. YES  : Go to  M5.
    2. NO  : Go to  M14.
  4. M4 CHECK THE EMTC A/C SIGNAL WITH THE A/C ON 
    • Key in OFF position.
    • Disconnect: IC C220
    • Key in ON position.
    • Select panel mode and press the A/C button on the HVAC module - EMTC.
      • Fig 1: Checking EMTC A/C Signal With A/C ON
      GF0041585Courtesy of FORD MOTOR CO.
    • Measure the resistance between IC C220-23, circuit CH434 (GY/YE), harness side and ground.
    • Is the resistance less than 5 ohms? 
    1. YES  : Go to  M5.
    2. NO  : Go to  M7.
  5. M5 CHECK THE AIR CONDITIONING COMPRESSOR CYCLING SWITCH (ACCS) PCM PID WITH THE A/C ON 
    • Key in OFF position.
      NOTE: For EMTC systems only.
    • Disconnect: For EMTC systems only, IC C220
    • Key in ON position.
      NOTE: For EMTC systems only.
    • Enter the following diagnostic mode on the diagnostic tool: ACCS PCM PID
    • Press the PANEL and A/C manual override buttons on the HVAC module - DATC and HVAC module - EATC or select MAX A/C on the HVAC module - EMTC.
    • Does the ACCS PCM PID read ON? 
    1. YES  : Go to  M6.
    2. NO  : Go to  M15.
  6. M6 CHECK THE AIR CONDITIONING CLUTCH (WAC/ACCR) PCM PID WITH THE A/C ON 
    • Enter the following diagnostic mode on the diagnostic tool: WAC/ACCR PCM PID
    • Does the WAC/ACCR PCM PID read ON? 
    1. YES  : Go to  M9.
    2. NO  : Go to  M15.
  7. M7 CHECK CIRCUIT CH434 (GY/YE) FOR AN OPEN 
    • Key in OFF position.
    • Disconnect: HVAC Module - EMTC C2357a
      • Fig 2: Checking Circuit CH434 (GY/YE) For An Open
      GF0041586Courtesy of FORD MOTOR CO.
    • Measure the resistance between HVAC module - EMTC C2357a-3, circuit CH434 (GY/YE), harness side and IC C220-23, circuit CH434 (GY/YE), harness side.
    • Is the resistance less than 5 ohms? 
    1. YES  : Go to  M8.
    2. NO  : REPAIR circuit CH434 (GY/YE) for an open. TEST the system for normal operation.
  8. M8 CHECK CIRCUIT CH434 (GY/YE) FOR A SHORT TO VOLTAGE 
    • Key in ON position.
      • Fig 3: Checking Circuit CH434 (GY/YE) For A Short To Voltage
      GF0041587Courtesy of FORD MOTOR CO.
    • Measure the voltage between HVAC module - EMTC C2357a-3, circuit CH434 (GY/YE), harness side and ground.
    • Is the voltage greater than 10 volts? 
    1. YES  : Go to  M15.
    2. NO  : REPAIR circuit CH434 (GY/YE) for a short to voltage. TEST the system for normal operation.
  9. M9 CHECK THE VOLTAGE AT THE A/C COMPRESSOR CLUTCH FIELD COIL 
    • Key in OFF position.
    • Disconnect: A/C Compressor Clutch Field Coil C100
    • Key in ON position.
    • Press the PANEL and A/C manual override buttons on the HVAC module - EATC and HVAC module - DATC or select MAX A/C on the HVAC module - EMTC.
      • Fig 4: Checking Circuit CH401 (VT/WH) For Short To Voltage
      GF0030271Courtesy of FORD MOTOR CO.
    • Measure the voltage between A/C compressor clutch field coil C100-B, circuit CH401 (VT/WH), harness side and ground.
    • Is the voltage greater than 10 volts? 
    1. YES  : Go to  M10.
    2. NO  : Go to  M12.
  10. M10 CHECK THE GROUND AT THE A/C COMPRESSOR CLUTCH FIELD COIL 
    • Key in OFF position.
      • Fig 5: Checking Ground At A/C Compressor Clutch Field Coil
      GF0030272Courtesy of FORD MOTOR CO.
    • Measure the resistance between A/C compressor clutch field coil C100-A, circuit GD121 (BK/YE), harness side and ground.
    • Is the resistance less than 5 ohms? 
    1. YES  : Go to  M11.
    2. NO  : REPAIR circuit GD121 (BK/YE) for an open. TEST the system for normal operation.
  11. M11 CHECK THE A/C COMPRESSOR CLUTCH AIR GAP 
      Fig 6: Checking A/C Compressor Clutch Air Gap
      GF0030273Courtesy of FORD MOTOR CO.
    • Measure the A/C compressor clutch air gap at 3 equally spaced locations between the clutch hub and the A/C compressor clutch pulley.
    • Is the A/C compressor clutch air gap greater than 0.6 mm (0.024 in)? 
    1. YES  : ADJUST the A/C compressor clutch gap. REFER to Air Conditioning (A/C) Clutch Air Gap Adjustment . TEST the system for normal operation.
    2. NO  : INSTALL a new A/C compressor clutch field coil. TEST the system for normal operation.
  12. M12 CHECK CIRCUIT SBB25 (RD) FOR VOLTAGE 
    • Key in OFF position.
    • Disconnect: A/C Clutch Relay
    • Key in ON position.
      • Fig 7: Checking Circuit SBB25 (RD) For Voltage
      GF0030274Courtesy of FORD MOTOR CO.
    • Measure the voltage between A/C clutch relay socket, circuit SBB25 (RD) and ground.
    • Is the voltage greater than 10 volts? 
    1. YES  : Go to  M13.
    2. NO  : VERIFY Battery Junction Box (BJB) fuse 25 (10A) is OK. If OK, REPAIR circuit SBB25 (RD) for an open. TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams article to identify the possible causes of the circuit short.
  13. M13 CHECK CIRCUIT CH401 (VT/WH) FOR AN OPEN 
    • Key in OFF position.
      • Fig 8: Checking Circuit CH401 (VT/WH) For An Open
      GF0030275Courtesy of FORD MOTOR CO.
    • Measure the resistance between A/C clutch relay socket pin 5, circuit CH401 (VT/WH) and A/C compressor clutch field coil C100-B, circuit CH401 (VT/WH), harness side.
    • Is the resistance less than 5 ohms? 
    1. YES  : Go to  M15.
    2. NO  : REPAIR circuit CH401 (VT/WH) for an open. TEST the system for normal operation.
  14. M14 CHECK THE MODULE CONNECTION 
    • Carry out the HVAC Module Cold Boot Process.
      • NOTE: DATC/EATC systems only.
    • Carry out the HVAC Module - Electronic Automatic Temperature Control (EATC) and HVAC Module - Dual Automatic Temperature Control (DATC) On-Demand Self Test.
    • Operate the system.
    • Does the concern return? 
    1. YES  : INSTALL a new HVAC module. REFER to CLIMATE CONTROL article. 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.
  15. M15 CHECK THE PCM CONNECTION 
    • Check 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 cause by a loose or corroded connector.
scientia non olet · About LEMON Manuals