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Pinpoint Test L: The A/C (Air Conditioning) Is Inoperative - No Diagnostic Trouble Codes (DTCS)

  1. Refer to MANUAL CLIMATE CONTROL SYSTEM for schematic and connector information.

    Normal Operation and Fault Conditions 

    When an A/C request is received by the PCM, the A/C clutch is engaged when all of the following conditions are met:

    • Excessively high or low refrigerant pressure from the A/C pressure transducer is not detected.
    • Ambient air temperature is above approximately 0°C (32.0°F).
    • Evaporator temperature is above approximately 1°C (33.8°F).
    • Engine coolant temperature conditions are within normal parameters.
    • Wide Open Throttle (WOT) condition is not present.
    • Engine torque conditions are within normal parameters.
    • Battery state of charge conditions are within normal parameters.

    For more information on A/C, REFER to: Climate Control System - Vehicles With: Dual Automatic Temperature Control (DATC) - System Operation and Component Description .

    Possible Sources 

    • Wiring, terminals or connectors
    • A/C system discharged or low refrigerant charge
    • Network concerns
    • A/C pressure transducer
    • Evaporator temperature sensor
    • Engine temperature sensors
    • A/C compressor clutch air gap
    • A/C compressor clutch field coil
    • A/C clutch SMART (FET) [non-serviceable, part of the BCMC also known as BJB ]
    • HVAC control module

    Visual Inspection and Pre-checks 

    • Verify the A/C compressor belt is OK.
    • Verify the A/C compressor clutch is engaged/operating.

    NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may cause damage to the connector.
    NOTE: Some Powertrain Control Module (PCM) Diagnostic Trouble Codes (DTCs) may inhibit Air Conditioning (A/C) operation. If any Powertrain Control Module (PCM) Diagnostic Trouble Codes (DTCs) are retrieved, diagnose those first. Refer to Diagnostic Trouble Code (DTC) Chart .

  2. L1 VERIFY THE AIR CONDITIONING (A/C) CLUTCH OPERATION

    • Start the engine. Observe the outside temperature display for proper operation.

    • On the HVAC controls, set the temperature to full cold, select PANEL and select the A/C button (indicator on).

    Does the A/C compressor clutch engage? 

    Yes  TEST the A/C system for normal operation. Carry out the Refrigerant System Tests. REFER to: Refrigerant System Tests - 2.3L EcoBoost (199kW/270PS) . REFER to: Refrigerant System Tests - 2.7L EcoBoost (238kW/324PS) .
    No  GO to L2 

  3. L2 RESET THE AMBIENT AIR TEMPERATURE (AAT) SENSOR

    • Ignition OFF.

    • Wait 1 minute.

    • Ignition ON.

    • Start the engine.

    • On the HVAC controls, set the temperature to full cold, select PANEL and select the A/C button (indicator on).

    Does the A/C compressor turn on? 

    Yes  TEST the A/C system for normal operation. CARRY OUT the Refrigerant System Tests. REFER to: Refrigerant System Tests - 2.3L EcoBoost (199kW/270PS) . REFER to: Refrigerant System Tests - 2.7L EcoBoost (238kW/324PS) .
    No  GO to L3 

  4. L3 CHECK THE A/C (AIR CONDITIONING) SYSTEM PRESSURE

    NOTE: Static refrigerant pressure, under perfect conditions, should approximately reflect ambient air temperature. Do not rely upon the static refrigerant pressure alone to determine if the system is properly charged. Refer to the current Ford Web Based Technical Training courses for basic HVAC system refrigerant operation.

    • Ignition OFF.

    • Connect the manifold gauge set.

    • Check for minimum A/C system pressure.

    Is the A/C system pressure above 290 kPa (42 psi)? 

    Yes  GO to L4 
    No  DIAGNOSE the A/C system for leaks. GO to Pinpoint Test AJ  After leak is repaired, RECHARGE the A/C system. REFER to: Air Conditioning (A/C) System Recovery, Evacuation and Charging .

  5. L4 CHECK THE COMMUNICATION NETWORK

    • Ignition ON.

    • Using a diagnostic scan tool, carry out the network test.

    Do the BCMC, the HVAC control module, and the PCM (as applicable) pass the network test? 

    Yes  GO to L5 
    No  DIAGNOSE the BCMC, the HVAC control module or PCM does not communicate with the diagnostic scan tool. REFER to: Controller Area Network (CAN) Module Communications Network .

  6. L5 COMPARE THE PCM (POWERTRAIN CONTROL MODULE) A/C (AIR CONDITIONING) PRESSURE SENSOR PID (PARAMETER IDENTIFICATION) WITH THE MANIFOLD GAUGE VALUE

    NOTE: The following pinpoint test step is tested in ambient temperature of approximately 21.1°C (70°F). As ambient temperatures near 38°C (100.4°F), the pressure value difference increases above +/- 15 psi (103 kPa) range.

    • With a manifold gauge set connected, compare the pressure readings of the manifold gauge set and the

      Access the PCM and monitor the ACP_PRESS (kPa) PID

    Are the pressure values of the manifold gauge set and the PID, dependent upon ambient temperatures, within +/- 103 kPa (15 psi)? 

    Yes  GO to L6 
    No  DIAGNOSE the A/C pressure transducer. GO to Pinpoint Test A 

  7. L6 COMPARE THE HVAC (HEATING, VENTILATION AND AIR CONDITIONING) CONTROL MODULE EVAPORATOR TEMPERATURE PID (PARAMETER IDENTIFICATION) TO THE PCM (POWERTRAIN CONTROL MODULE) AMBIENT AIR TEMPERATURE PID (PARAMETER IDENTIFICATION)

    • Ignition OFF.

    • Allow the vehicle exterior and interior to stabilize to ambient temperature. This can take a soak period of at least 6 hours.

    • Ignition ON.

    Access the PCM and monitor the AAT (Deg C) PID

    Access the HVAC and monitor the EVAP_TEMP (Deg C) PID

    Are the temperature values similar [typically within 18°C or 30°F of each other]? 

    Yes  GO to L7 
    No  DIAGNOSE the suspect temperature sensor. For Ambient Air Temperature (AAT) sensor or Outside Air Temperature Display concerns, REFER to: Instrumentation, Message Center and Warning Chimes . For evaporator temperature sensor concerns, GO to Pinpoint Test F 

  8. L7 COMPARE THE PCM (POWERTRAIN CONTROL MODULE) INTAKE AIR TEMPERATURE PID (PARAMETER IDENTIFICATION) AND THE OTHER TEMPERATURE SENSOR READINGS TO THE PCM (POWERTRAIN CONTROL MODULE) AMBIENT AIR TEMPERATURE PID (PARAMETER IDENTIFICATION)

    NOTE: Compare multiple engine sensor readings to the ambient temperature to determine sensors are reading correctly. A faulty sensor can cause the Powertrain Control Module (PCM) to disable the Air Conditioning (A/C) compressor with or without a Diagnostic Trouble Code (DTC).

    Monitor the temperature Parameter Identifications (PIDs) (as applicable):

    • Access the PCM and monitor the AAT (Deg C) PID
    • Access the PCM and monitor the CAC_T (Deg C) PID
    • Access the PCM and monitor the CHT (Deg C) PID
    • Access the PCM and monitor the ECT (Deg C) PID
    • Access the PCM and monitor the IAT (Deg C) PID
    • Access the PCM and monitor the IAT2 (Deg C) PID

    Are the temperature values similar [typically within 18°C or 30°F of each other]? 

    Yes  GO to L8 
    No  DIAGNOSE the suspect PCM temperature sensor. REFER to the appropriate Service Article under Engine .

  9. L8 CHECK THE HVAC (HEATING, VENTILATION AND AIR CONDITIONING) CONTROL MODULE A/C (AIR CONDITIONING) SWITCH PID (PARAMETER IDENTIFICATION) WITH THE A/C (AIR CONDITIONING) ON

    • Access the HVAC and monitor the CC_SW_ACPID.

    • On the HVAC controls, select PANEL and then press the A/C button (indicator ON).

    Does the PID display ON or Yes when the button is pressed? 

    Yes  GO to L9 
    No  GO to L13 

  10. L9 CHECK THE PCM (POWERTRAIN CONTROL MODULE) A/C (AIR CONDITIONING) REQUEST SIGNAL PID (PARAMETER IDENTIFICATION) WITH THE A/C (AIR CONDITIONING) ON

    Access the PCM and monitor the AC_REQPID

    • On the HVAC controls, select PANEL and then press the A/C button (indicator ON).

    Does the PID display ON or Yes when the button is pressed? 

    Yes  GO to L10 
    No  GO to L13 

  11. L10 COMMAND THE A/C (AIR CONDITIONING) COMPRESSOR ON

    Access the PCM and control the ACC_CMDPID

    Does the A/C compressor turn on? 

    Yes  TURN OFF the active command PID. GO to L14 
    No  TURN OFF the active command PID. GO to L11 

  12. L11 CHECK THE A/C (AIR CONDITIONING) COMPRESSOR CLUTCH FIELD COIL GROUND CIRCUIT FOR AN OPEN

    • Ignition OFF.

    • Disconnect A/C clutch and A/C clutch field coil C100

    • Measure:
      Positive Lead Measurement / Action Negative Lead
      C100 Pin 2
      GFD758228Courtesy of FORD MOTOR COMPANY
      		 Ground

    Is the resistance less than 3 ohms? 

    Yes  GO to L12 
    No  REPAIR the circuit.

  13. L12 CHECK THE A/C (AIR CONDITIONING) CLUTCH SMART FET (FIELD-EFFECT TRANSISTOR) OUTPUT TO THE A/C (AIR CONDITIONING) COMPRESSOR CLUTCH FIELD COIL WITH A TEST LAMP

    NOTE: The following step uses a test lamp to simulate normal circuit loads. Use only a Rotunda Test Lamp (SGT27000) or 250- 300mA incandescent bulb test lamp. To avoid connector terminal damage, use the Rotunda Flex Probe kit for the test lamp probe connection to the vehicle. Do not use the test lamp probe directly on any connector.

    • Ignition OFF.

    • Connect a 12-volt incandescent test lamp between:
      Positive Lead Measurement / Action Negative Lead
      C100 Pin 1
      GFD760042Courtesy of FORD MOTOR COMPANY
      		 C100 Pin 2

    • Ignition ON.

    Access the PCM and control the ACC_CMDPID

    Does the test lamp illuminate? 

    Yes  INSTALL a new A/C clutch and A/C clutch field coil. REFER to: Air Conditioning (A/C) Clutch and Air Conditioning (A/C) Clutch Field Coil - 2.3L EcoBoost (199kW/270PS) . REFER to: Air Conditioning (A/C) Clutch and Air Conditioning (A/C) Clutch Field Coil - 2.7L EcoBoost (238kW/324PS) 
    (412-00 Climate Control System - General Information, Removal and Installation). CLEAR all Diagnostic Trouble Codes (DTCs). TEST the system for normal operation.
    No  DIAGNOSE the A/C clutch Smart FET control input circuit GO to Pinpoint Test B  and DIAGNOSE the control output circuit GO to Pinpoint Test C 

  14. L13 CHECK FOR CORRECT HVAC (HEATING, VENTILATION AND AIR CONDITIONING) CONTROL MODULE OPERATION

    • Ignition OFF.

    • Disconnect and inspect all HVAC control module electrical connectors (if not previously disconnected).

    • Repair:

      • corrosion (install new connector or terminal - clean module pins)
      • damaged or bent pins - install new terminals or pins
      • pushed-out pins - install new pins as necessary

    • Connect all HVAC control module electrical connectors. Make sure they seat and latch correctly.

    • Operate the system and determine if the concern is still present.

    Is the concern still present? 

    Yes  CHECK OASIS for any applicable service articles: TSB, GSB, SSM or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, INSTALL a new HVAC control module. REFER to: Heating, Ventilation and Air Conditioning (HVAC) Control Module .
    No  The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. ADDRESS the root cause of any connector or pin issues.

  15. L14 CHECK FOR AN INPUT DISABLING THE A/C (AIR CONDITIONING) CLUTCH

    NOTE: The Powertrain Control Module (PCM) strategy may disable the Air Conditioning (A/C) compressor operation. If the A/C compressor clutch can be commanded on using a diagnostic scan tool Powertrain Control Module (PCM) Parameter Identifications (PIDs) Active Commands, Powertrain Control Module (PCM) replacement will not resolve the condition.

    • Diagnose the PCM not energizing the A/C clutch SMART FET (field-effect transistor) using the suggestions in the table below.
      A/C Clutch Engagement is inhibited because strategy has not yet detected hardware that indicates vehicle is equipped with A/C
      A/C Clutch Engagement is inhibited because the strategy is operating in Ignition System Failure Mode
      A/C Clutch Engagement is inhibited because the (ECU) received a Request to Command the A/C Off
      A/C Clutch Engagement is inhibited because the engine has not yet reached a stable running mode after starting
      A/C Clutch Engagement is inhibited because the A/C Discharge (Head) Pressure is Too High
      A/C Clutch Engagement is inhibited because the Engine Coolant Temperature is Too High
      A/C Clutch Engagement is inhibited to Prevent Frost and Ice Build Up on the Evaporator
      A/C Clutch Engagement is inhibited to Prevent an Engine Stall during a Low Engine Speed condition
      A/C Clutch Engagement is inhibited to Protect the Compressor from a Compressor Over-speed condition
      A/C Clutch Engagement is inhibited to temporarily make more power available when Accelerator Pedal is Fully Depressed
      A/C Clutch Engagement is inhibited because Low A/C Refrigerant Charge has been detected
      A/C Clutch Engagement is inhibited to Protect the Compressor from Operating at Too Low of an Ambient Temperature
      A/C Clutch Engagement is inhibited due to Missing Climate Control Message
      A/C Clutch Engagement is inhibited because the strategy is operating in Failsafe Cooling Mode
      A/C Clutch Engagement is inhibited to Protect the Clutch from Damage because the Compressor Load and Speed are Too High
      A/C Clutch Engagement is inhibited by the off portion of the A/C Cycling Strategy invoked to manage High Engine Temperature
      A/C Clutch Engagement is inhibited due to Low Battery State of Charge
      A/C Clutch Engagement is inhibited to Protect the Variable Displacement Compressor from Operating at Too Low of a Temperature
      A/C Clutch Engagement is inhibited to improve Brake Booster Vacuum
      A/C Clutch Engagement is inhibited because Evaporator Temperature is sufficiently low and compressor was at minimum displacement
      A/C Clutch Engagement is inhibited (Disabled) because the Evaporator Temperature is sufficiently below the target temperature
      A/C Clutch Engagement is inhibited to satisfy A/C Clutch minimum off time
      A/C Clutch Engagement is inhibited Due to Request from Torque Control Strategy (to Temporarily Make More Power Available)
      A/C Clutch Engagement is inhibited to Prevent Engine Stalling
      A/C Clutch Engagement is inhibited Due to Request to Disable A/C from Stop-Start Strategy
      A/C Clutch Engagement is inhibited (Delayed) to make Power Available for Power Steering
      A/C Clutch Engagement Is Inhibited Due To State Of Auxiliary A/C Disable (Typically A Pressure Or Temperature) Switch 1 input
      A/C Clutch Engagement is inhibited due to state of auxiliary A/C Disable (Typically a Pressure or Temperature) Switch 2 input

    Are any of the conditions described above not within normal parameters? 

    Yes  DIAGNOSE the condition found to be disabling the A/C clutch. REFER to the appropriate Engine Service Article .
    No  The A/C compressor clutch can be commanded on using the diagnostic scan tool PCM active command PID. The A/C inoperative concern may be caused by an intermittent condition due to a component or module connection, wiring or pin issue. ADDRESS the root cause of any connector or pin issues. CHECK the vehicle service history for recent service actions that have replaced modules. This condition may be due to incomplete or incorrect PMI procedures.
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