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

WARNING: This page is about a different car, the 2018 Ford F-550 Super Duty, 2018 Ford F-450 Super Duty, 2018 Ford F-350 Super Duty, and 2018 Ford F-250 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Some PCM Diagnostic Trouble Codes (DTCs) may inhibit A/C operation. If any PCM Diagnostic Trouble Codes (DTCs) are retrieved, diagnose those first. Refer to DTC Chart: Powertrain Control Module (PCM) .

G1 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.

With the manifold gauge set connected, check for minimum A/C system pressure.

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

Yes

GO to G2

No	CHECK the A/C system for leaks. Refer to: Electronic Leak Detection . Refer to: Fluorescent Dye Leak Detection . After the leak is repaired, RECHARGE the A/C system. Refer to: Air Conditioning (A/C) System Recovery, Evacuation and Charging .

G2 CHECK THE COMMUNICATION NETWORK

Ignition ON.

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

Do the FCIM and the PCM pass the network test?

Yes

GO to G3

No	DIAGNOSE the FCIM or PCM does not communicate with the diagnostic scan tool. Refer to: Communications Network .

G3 CHECK THE PCM (POWERTRAIN CONTROL MODULE) A/C (AIR CONDITIONING) PRESSURE SENSOR (ACP_PRESS) PID (PARAMETER IDENTIFICATION)

Ignition ON.

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

With a manifold gauge set connected, compare the pressure readings of the manifold gauge set and the PCM ACP_PRESS PID.

Are the pressure values of the manifold gauge set and the ACP_PRESS PCM PID within ± 103 kPa (15 psi)?

Yes	If equipped with electric cooling fan, GO to G4. If not equipped with electric cooling fan, GO to G5

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

G4 ELECTRIC COOLING FAN FUNCTIONAL CHECK

Ignition ON.

Using a diagnostic scan tool, carry out the PCM KOEO self-test.

Does the electric cooling fan operate during the KOEO self-test?

Yes

GO to G5

No	DIAGNOSE the electric cooling fan operation. REFER to Engine Controls - Symptom Charts (Diesel) or ENGINE CONTROLS - SYMPTOM CHARTS (EXCEPT DIESEL & HYBRID) .

G5 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 PCM to disable the A/C with or without a DTC.

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

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

Monitor the AAT, CACT, CHT, ECT, IAT, IAT2, MAF, MAPT, TCB and TCIPT Parameter Identifications (PIDs) (as applicable).

Are the temperature values similar (typically within 18 °C (32.4 °F))?

Yes

GO to G6

DIAGNOSE the suspect temperature sensor. REFER to Instrumentation, Message Center And Warning Chimes for Ambient Air Temperature (AAT) sensor or Outside Air Temperature Display concerns. For all other temperature sensor concerns, REFER to Engine Controls - Symptom Charts (Diesel) or ENGINE CONTROLS - SYMPTOM CHARTS (EXCEPT DIESEL & HYBRID) .

G6 COMPARE THE FCIM (FRONT CONTROLS INTERFACE MODULE) A/C EVAPORATOR TEMPERATURE (EVAP_TEMP) PID (PARAMETER IDENTIFICATION) TO THE PCM (POWERTRAIN CONTROL MODULE) AMBIENT AIR TEMPERATURE (AAT) PID (PARAMETER IDENTIFICATION)

Ignition OFF.

Allow the vehicle exterior and interior to stabilize to ambient temperature.

Ignition ON.

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

Monitor and record the PCM PID AAT.

Using a diagnostic scan tool, view the FCIM Parameter Identification (PIDs).

Monitor and record the FCIM PID EVAP_TEMP.

Are the temperature values similar (typically within 18 °C (32.4 °F))?

Yes	If equipped with the active grille shutter system, GO to G7. If not equipped with the active grille shutter system, GO to G8

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

G7 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.

Using a diagnostic scan tool, view PCM PID.

Using a diagnostic scan tool, select the PCM PID GRILL_A_CMD and 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 G8

No	DIAGNOSE the active grille shutter is inoperative or does not operate correctly. Refer to the appropriate procedure in Body Panel System - Front End Body Panels .

G8 CHECK THE FCIM (FRONT CONTROLS INTERFACE MODULE) A/C (AIR CONDITIONING) SWITCH (CC_SW_AC) PID (PARAMETER IDENTIFICATION) WITH THE A/C (AIR CONDITIONING) ON
- Using a diagnostic scan tool, view FCIM Parameter Identifications (PIDs).
- Monitor the CC_SW_AC PID.
Does the PID display Active or On when the button is pressed?

Yes GO to G9

No GO to G17

G9 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.
- Using a diagnostic scan tool, monitor the PCM AC_REQ PID.
- 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 G11

No GO to G10

G10 RESET THE AMBIENT AIR TEMPERATURE (AAT) SENSOR

On the HVAC controls, press the A/C and Recirc buttons simultaneously, 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).

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 procedure in the appropriate Climate Control Systems article.

GO to G11

G11 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
- Using a diagnostic scan tool, activate the PCM ACC_CMD PID.
Does the A/C compressor turn on?

Yes GO to G18

No GO to G12

G12 CHECK THE VOLTAGE TO THE A/C (AIR CONDITIONING) CLUTCH RELAY

Ignition OFF.

Disconnect the A/C clutch relay.

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
A/C clutch relay socket 1	Courtesy of FORD MOTOR COMPANY	Ground
A/C clutch relay socket 3	Courtesy of FORD MOTOR COMPANY	Ground

Are the voltages greater than 11 volts?

Yes

GO to G13

No	VERIFY BJB fuses 3 (20A) and 16 (10A) are OK. If not OK, REFER to the OEM Wiring Diagrams to identify the possible causes of the circuit short. If OK, REPAIR the circuit.

G13 BYPASS THE A/C (AIR CONDITIONING) CLUTCH RELAY

Ignition OFF.

Connect a fused jumper wire:

Positive Lead	Measurement / Action	Negative Lead
A/C clutch relay socket 3	Courtesy of FORD MOTOR COMPANY	A/C clutch relay socket 5

Ignition ON.

Does the A/C compressor clutch engage?

Yes	REMOVE the fused jumper wire. INSTALL a new A/C clutch relay.

No	LEAVE the fused jumper wire installed. GO to G14

G14 CHECK THE A/C (AIR CONDITIONING) COMPRESSOR CLUTCH FIELD COIL VOLTAGE SUPPLY CIRCUIT FOR AN OPEN

Disconnect A/C compressor clutch field coil C100 .

Measure:

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

Is the voltage greater than 11 volts?

Yes	REMOVE the fused jumper wire. GO to G15

No	REMOVE the fused jumper wire. REPAIR the circuit.

G15 CHECK THE A/C (AIR CONDITIONING) COMPRESSOR CLUTCH FIELD COIL GROUND CIRCUIT FOR AN OPEN

Ignition OFF.

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 G16

No	REPAIR the circuit.

G16 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	ADJUST the A/C compressor clutch air gap. Refer to: Air Conditioning (A/C) Clutch Air Gap Adjustment .

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

G17 CHECK FOR CORRECT FCIM (FRONT CONTROLS INTERFACE MODULE) OPERATION

Ignition OFF.

Disconnect and inspect all FCIM connectors.

Repair:
- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins
- pushed-out pins - install new pins as necessary

Reconnect all FCIM 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 Technical Service Bulletins (TSBs). If a TSB exists for this concern, DISCONTINUE this test and FOLLOW TSB instructions. If no Technical Service Bulletins (TSBs) address this concern, Refer to FCIM HARDWARE TESTING .

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.

G18 CHECK FOR AN INPUT DISABLING THE A/C (AIR CONDITIONING) CLUTCH RELAY

NOTE: The PCM strategy may disable the A/C compressor operation. If the A/C compressor clutch can be commanded on using IDS PCM Parameter Identifications (PIDs) Active Commands, PCM replacement will not resolve the condition.

Diagnose the PCM not energizing the A/C clutch relay using the suggestions in the table below. Refer to the reference value information in Engine Controls - Reference Values (Diesel) or Engine Controls - Reference Values (Except Diesel & Hybrid) .

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 Service Information or the Engine Controls - Symptom Charts (Diesel) or ENGINE CONTROLS - SYMPTOM CHARTS (EXCEPT DIESEL & HYBRID) .

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