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

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 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: PCM .

I1 CHECK THE A/C (AIR CONDITIONING) SYSTEM PRESSURE

Ignition OFF.

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

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

Yes

GO to I2

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

I2 CHECK THE COMMUNICATION NETWORK
- Ignition ON.
- Using a diagnostic scan tool, carry out the network test.
Do the BCM and the PCM pass the network test?

Yes GO to I3

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

I3 CHECK THE PCM (POWERTRAIN CONTROL MODULE) A/C (AIR CONDITIONING) PRESSURE SENSOR (ACP_PRESS) PID (PARAMETER IDENTIFICATION)
- Ignition ON.
- Using a diagnostic scan tool, monitor the PCM ACP_PRESS PID.
- With the manifold gauge set connected, compare the pressure readings of the manifold gauge set and the ACP_PRESS PID.
Are the pressure values of the manifold gauge set and the ACP_PRESS PCMPID within ± 103 kPa (15 psi)?

Yes GO to I4

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

I4 COMPARE THE EVAPORATOR TEMPERATURE SENSOR RESISTANCE TO THE PCM (POWERTRAIN CONTROL MODULE) AMBIENT AIR TEMPERATURE (AAT) PID (PARAMETER IDENTIFICATION)

Ignition OFF.

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

Disconnect evaporator temperature sensor C296.

Measure component side

Positive Lead	Measurement / Action	Negative Lead
C296 pin 1 (Component Side)	Courtesy of FORD MOTOR COMPANY	C296 pin 3 (Component Side)

Compare the evaporator temperature sensor measured resistance with the table below.

Ambient Temperature °F (°C)	Resistance
-4.0 °F (-20 °C)	28.6 K ohms - 30.5 K ohms
32.0 °F (°C)	9.7 K ohms - 10.2 K ohms
68.0 °F (20 °C)	3.7 K ohms - 3.9 K ohms
77.0 °F (25 °C)	2.9 K ohms - 3.1 K ohms
103.9 °F (40 °C)	1.5 K ohms - 1.7 K ohms
139.9 °F (60 °C)	728 ohms - 787 ohms

Connect evaporator temperature sensor C296.

Ignition ON.

Using a diagnostic scan tool, monitor the PCM AAT PID.

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

Yes

GO to I5

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

I5 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 I6

No	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 (Except Diesel & Hybrid) .

I6 RESET THE AMBIENT AIR TEMPERATURE (AAT) SENSOR
- On the HVAC controls, press the A/C (air conditioning) 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. REFER to: Refrigerant System Tests - 2.5L Duratec (125kW/170PS) .

No GO to I7

I7 CHECK THE A/C (AIR CONDITIONING) ON SWITCH CIRCUIT FOR A SHORT TO VOLTAGE

Ignition OFF.

Disconnect HVAC control module C2357A.

Disconnect BCM C2280C.

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C2357A-5	Courtesy of FORD MOTOR COMPANY	Ground

Is any voltage present?

Yes	REPAIR the circuit.

GO to I8

I8 CHECK THE A/C (AIR CONDITIONING) ON SWITCH CIRCUIT FOR A SHORT TO GROUND

Ignition OFF.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C2357A-5	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance greater than 10, 000 ohms?

Yes

GO to I9

No	REPAIR the circuit.

I9 CHECK THE A/C (AIR CONDITIONING) ON SWITCH CIRCUIT FOR AN OPEN

Measure:

Positive Lead	Measurement / Action	Negative Lead
C2357A-5	Courtesy of FORD MOTOR COMPANY	C2280C-10

Is the resistance less than 3 ohms?

Yes

GO to I10

No	REPAIR the circuit.

I10 CHECK THE PCM (POWERTRAIN CONTROL MODULE) A/C (AIR CONDITIONING) REQUEST SIGNAL (AC_REQ) PID (PARAMETER IDENTIFICATION) WITH THE A/C (AIR CONDITIONING) ON
- Connect HVAC control module C2357A.
- Connect BCM C2280C.
- 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 ON or Yes when the button is pressed?

Yes GO to I11

No GO to I17

I11 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 I18

No GO to I12

I12 CHECK THE VOLTAGE TO THE A/C (AIR CONDITIONING) CLUTCH RELAY

Ignition OFF.

Disconnect the A/C clutch relay.

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 I13

No	VERIFY BJB fuses 23 (5A) and 27 (15A) are OK. If OK, REPAIR the circuit. If OK, REPAIR the circuit. If not OK, REFER to OEM Electrical Wiring Diagram Introduction to identify the possible causes of the circuit short.

I13 BYPASS THE A/C (AIR CONDITIONING) CLUTCH RELAY

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

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 I14

I14 CHECK THE A/C (AIR CONDITIONING) COMPRESSOR CLUTCH FIELD COIL VOLTAGE SUPPLY CIRCUIT FOR AN OPEN

Disconnect A/C clutch field coil C1680 (2.5L engines).

For 2.5L, measure:

Positive Lead	Measurement / Action	Negative Lead
C1680-1	Courtesy of FORD MOTOR COMPANY	Ground

Is the voltage greater than 11 volts?

Yes	REMOVE the fused jumper wire. GO to I15

No	REMOVE the fused jumper wire.REPAIR the circuit.

I15 CHECK THE A/C (AIR CONDITIONING) COMPRESSOR CLUTCH FIELD COIL GROUND CIRCUIT FOR AN OPEN

For 2.5L, measure:

Positive Lead	Measurement / Action	Negative Lead
C1680-2	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance less than 3 ohms?

Yes

GO to I16

No	REPAIR the circuit.

I16 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 and field coil. REFER to: Air Conditioning (A/C) Clutch and Air Conditioning (A/C) Clutch Field Coil .

I17 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 Technical Service Bulletins (TSBs). If a TSB exists for this concern, DISCONTINUE this test and FOLLOW the TSB instructions. If no Technical Service Bulletins (TSBs) address this concern, INSTALL a new HVAC control module. REFER to: Climate Control Assembly .

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.

I18 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 (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 (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.