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

WARNING: This page is about a different car, the 2021 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

Refer to Wiring Diagrams MANUAL CLIMATE CONTROL SYSTEM for schematic and connector information.
Normal Operation and Fault Conditions

A/C Request, REFER to: Climate Control System - Vehicles With: Electronic Manual Temperature Control (EMTC) - 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
- Electric cooling fan
- Active grill shutters
- 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
- BCM fuse 12 (7.5A)
NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage 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 .

F1 EXTERNALLY CONTROLLED VARIABLE DISPLACEMENT COMPRESSOR (EVDC) PERFORMANCE CHECK WITH THE AC COMPRESSOR ELECTRONIC CONTROL VALVE TESTER

NOTE: The following pinpoint test step uses the EVDC®100 Electronic Variable Displacement A/C Compressor Control Valve Tester, available on the Ford Rotunda website.

NOTE: Proper Air Conditioning (A/C) system diagnosis on a vehicle's compressor is dependent on correct refrigerant system charge and tested in ambient temperatures above 21.1 deg.C (70 deg.F).

Test the EVDC compressor displacement, following the instructions in the user manual supplied with the Model EVDC®100 A/C Compressor Electronic Control Valve Tester.

Did the suction low side pressure decrease or the high side pressure increase?

Yes	The Externally Controlled Variable Displacement Compressor (EVDC) is able to change the displacement. Do not replace the compressor. GO to F2

No	GO to Pinpoint Test Q

F2 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 F3

No	CHECK the A/C system for leaks. REFER to the appropriate GENERAL PROCEDURES . After leak is repaired, RECHARGE the A/C system. REFER to the appropriate GENERAL PROCEDURES .

F3 CHECK THE COMMUNICATION NETWORK

Ignition ON.

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

Do the HVAC control module and the PCM pass the network test?

Yes

GO to F4

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

F4 CHECK THE PCM (POWERTRAIN CONTROL MODULE) A/C (AIR CONDITIONING) PRESSURE SENSOR (ACP_PRESS) PID (PARAMETER IDENTIFICATION)

NOTE: The following pinpoint test step is tested in ambient temperature of approximately 21.1 deg.C (70 deg.F). As ambient temperatures near 38 deg.C (100.4 deg.F), the pressure value difference increases above +/- 15 psi (103 kPa) range.
- Access the PCM and monitor the ACP_PRESS (kPa) PID
Are the pressure values of the manifold gauge set and the ACP_PRESS PCMPID, dependent upon ambient temperatures, within +/- 103 kPa (15 psi)?

Yes If equipped with electric cooling fan, GO to F5 If not equipped with electric cooling fan, GO to F6

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

F5 ELECTRIC COOLING FAN FUNCTIONAL CHECK
- Activate the electric cooling fan Parameter Identifications (PIDs) (as applicable):
  - Access the PCM and control the FANELC_CMD (% Duty Cycle) PID
  - Access the PCM and control the FAN_DSD (%) PID
  - Access the PCM and control the FANSPD_DSD (Rpm) PID
Does the electric cooling fan operate when commanded ON?

Yes GO to F6

No DIAGNOSE the electric cooling fan operation. REFER to the appropriate Engine System article for the procedure.

F6 RESET THE AMBIENT AIR TEMPERATURE (AAT) SENSOR

Multi-button reset method:
- On the HVAC controls, press the A/C (air conditioning) and Recirc buttons simultaneously for 5 seconds, then release both. Within 2 seconds press A/C button again.
- Start the engine.
- On the HVAC controls, set the temperature to full cold, select PANEL and select the A/C button (indicator on).
- If the A/C compressor now turns on, RETEST the A/C system for normal operation. CARRY OUT the refrigerant system tests. Refer to the appropriate Refrigerant System Tests procedure in GENERAL PROCEDURES .
- If the A/C compressor does not turn on with the multi-button press method, follow the driving reset method.

Driving reset method:
- Start the engine.
- Safely drive the vehicle at speeds consistently about 20 MPH for at least 5 minutes to update the Filtered AAT signal.
- Park the vehicle and turn the ignition off.
- Wait one minute.
- 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	RETEST the A/C system for normal operation. CARRY OUT the refrigerant system tests. Refer to the appropriate Refrigerant System Tests in the appropriate Climate Control System article.

GO to F7

F7 COMPARE THE PCM (POWERTRAIN CONTROL MODULE) INTAKE AIR TEMPERATURE (IAT) PID (PARAMETER IDENTIFICATION) AND THE OTHER TEMPERATURE SENSOR READINGS TO THE PCM (POWERTRAIN CONTROL MODULE) AMBIENT AIR TEMPERATURE (AAT) 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).

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.

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 deg.C (32.4 deg.F)?

Yes

GO to F8

DIAGNOSE the suspect temperature sensor. REFER to the appropriate Instrumentation, Message Center and Warning Chimes article for Ambient Air Temperature (AAT) sensor or Outside Air Temperature Display concerns. For all other temperature sensor concerns, REFER to the appropriate Engine System article, Diagnosis and Testing information.

F8 COMPARE THE HVAC (HEATING, VENTILATION AND AIR CONDITIONING) CONTROL MODULE EVAPORATOR TEMPERATURE (EVAP_TEMP) PID (PARAMETER IDENTIFICATION) TO THE PCM (POWERTRAIN CONTROL MODULE) AMBIENT AIR TEMPERATURE (AAT) PID (PARAMETER IDENTIFICATION)

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 deg.C (32.4 deg.F)?

Yes	If equipped with the active grille shutter system, GO to F9If not equipped with the active grille shutter system, GO to F10

No	DIAGNOSE the evaporator temperature sensor. GO to Pinpoint Test M

F9 VERIFY THE GRILLE SHUTTER OPERATION USING THE PCM (POWERTRAIN CONTROL MODULE) GRILL SHUTTER A POSITION - COMMANDED (GRILL_A_CMD) PID (PARAMETER IDENTIFICATION)
- Start the engine and allow it to idle for at least 30 seconds to allow for the grille shutter calibration to complete.
- Access the PCM and control the GRILL_A_CMD (% Open) PIDand command the grille shutter from 100% (open) to 0% (closed) while observing the grille shutter operation from the front of the vehicle.
Does the grille shutter fully open and close when commanded by the scan tool?

Yes GO to F10

No DIAGNOSE the active grille shutter is inoperative or does not operate correctly. REFER to: Active Grille Shutter .

F10 CHECK THE HVAC (HEATING, VENTILATION AND AIR CONDITIONING) CONTROL MODULE A/C (AIR CONDITIONING) SWITCH (CC_SW_AC) 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 Active or On when the A/C button is pressed?

Yes GO to F11

No GO to F19

F11 CHECK THE PCM (POWERTRAIN CONTROL MODULE) A/C (AIR CONDITIONING) REQUEST SIGNAL (AC_REQ) PID (PARAMETER IDENTIFICATION) WITH THE A/C (AIR CONDITIONING) ON
- Start the engine.
- Access the PCM and monitor the AC_REQUESTPID
  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 Yes when the button is pressed?

Yes GO to F12

No GO to F19

F12 CHECK THE PCM (POWERTRAIN CONTROL MODULE) A/C (AIR CONDITIONING) COMPRESSOR COMMANDED STATE (ACC_CMD) PID (PARAMETER IDENTIFICATION) WITH THE A/C (AIR CONDITIONING) COMMANDED ON
- For gasoline engines
  Access the PCM and control the ACC_CMDPID
  
  For diesel engines
  
  Access the PCM and control the AC_ClutchPID
Does the A/C compressor turn on?

Yes GO to F20

No GO to F13

F13 CHECK THE A/C (AIR CONDITIONING) CLUTCH RELAY CONTROL CIRCUIT FOR A SHORT TO VOLTAGE

Ignition OFF.

Disconnect BJB C1035B.

Disconnect PCM, 2.7L C1232B, 3.3L C1551B, 3.5L C175B, 5.0L C1381B or 3.0L Power Stroke Diesel C1233B.

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C1035B-29	Courtesy of FORD MOTOR COMPANY	Ground

Is any voltage present?

Yes	REPAIR the circuit.

GO to F14

F14 CHECK THE A/C (AIR CONDITIONING) CLUTCH RELAY CONTROL CIRCUIT FOR AN OPEN

Ignition OFF.

Measure:

2.7L

Positive Lead	Measurement / Action	Negative Lead
C1035B-29	Courtesy of FORD MOTOR COMPANY	C1232B-44

3.3L

Positive Lead	Measurement / Action	Negative Lead
C1035B-29	Courtesy of FORD MOTOR COMPANY	C1551B-44

3.5L

Positive Lead	Measurement / Action	Negative Lead
C1035B-29	Courtesy of FORD MOTOR COMPANY	C175B-44

5.0L

Positive Lead	Measurement / Action	Negative Lead
C1035B-29	Courtesy of FORD MOTOR COMPANY	C1381B-44

3.0L Power Stroke Diesel

Positive Lead	Measurement / Action	Negative Lead
C1035B-29	Courtesy of FORD MOTOR COMPANY	C1233B-68

Is the resistance less than 3 ohms?

Yes

GO to F15

No	REPAIR the circuit.

F15 CHECK THE A/C (AIR CONDITIONING) COMPRESSOR CLUTCH FIELD COIL GROUND CIRCUIT FOR AN OPEN

Disconnect A/C compressor clutch field coil C100.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C100-2	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance less than 3 ohms?

Yes

GO to F16

No	REPAIR the circuit.

F16 CHECK THE A/C (AIR CONDITIONING) COMPRESSOR CLUTCH FIELD COIL VOLTAGE SUPPLY CIRCUIT FOR AN OPEN

Disconnect BJB C1035C.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C1035C-5	Courtesy of FORD MOTOR COMPANY	C100-1

Is the resistance less than 3 ohms?

Yes

GO to F17

No	REPAIR the circuit.

F17 CHECK THE AIR CONDITIONING CLUTCH RELAY OPERATION

Connect PCM, 2.7L C1232B, 3.3L C1551B, 3.5L C175B, 5.0L C1381B or 3.0L Power Stroke Diesel C1233B.

Connect BJB C1035B.

Connect BJB C1035C.

Ignition ON.

Using a diagnostic scan tool, view the PCM Parameter Identifications (PIDs).

For gasoline engines
Access the PCM and control the ACC_CMDPID

For diesel engines

Access the PCM and control the AC_ClutchPID

Measure:

Positive Lead	Measurement / Action	Negative Lead
C100-1	Courtesy of FORD MOTOR COMPANY	Ground

Is the voltage greater than 11 volts?

Yes	TURN OFF the active command PID. GO to F18

No	TURN OFF the active command PID. INSTALL a new BCMC [also known as BJB]. REFER to: Body Control Module C (BCMC) .

F18 CHECK THE A/C (AIR CONDITIONING) COMPRESSOR CLUTCH AIR GAP

Measure the A/C compressor clutch air gap at 3 equally spaced locations between the clutch hub and the A/C compressor clutch pulley. REFER to: Air Conditioning (A/C) Clutch Air Gap Adjustment .

Is the A/C compressor clutch air gap greater than 0.6 mm (0.0236 in)?

Yes

If available, ADJUST the A/C compressor clutch air gap. REFER to: Air Conditioning (A/C) Clutch Air Gap Adjustment . If unable to adjust the clutch air gap, INSTALL a new A/C compressor clutch and A/C clutch field coil. REFER to: Air Conditioning (A/C) Clutch and Air Conditioning (A/C) Clutch Field Coil .

No	INSTALL a new A/C compressor clutch and A/C clutch field coil. REFER to: Air Conditioning (A/C) Clutch and Air Conditioning (A/C) Clutch Field Coil .

F19 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.

F20 CHECK FOR AN INPUT DISABLING THE A/C (AIR CONDITIONING) CLUTCH RELAY

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 relay 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 relay. REFER to the appropriate Engine System article, Diagnosis and Testing information.

The A/C compressor clutch can be commanded on using a 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.