Pinpoint Test K: The Air Conditioning (A/C) Is Inoperative
Climate Control System
Pinpoint Tests
Pinpoint Test K: The Air Conditioning (A/C) is Inoperative
Refer to Wiring Diagram Set 54 (Escape/Mariner, Escape Hybrid/Mariner Hybrid), Manual Climate Control System for schematic and connector information. Diagrams By Number
Refer to Wiring Diagram Set 55 (Escape/Mariner, Escape Hybrid/Mariner Hybrid), Automatic Climate Control System for schematic and connector information. Diagrams By Number
Normal Operation
Under normal operation, when A/C is requested the HVAC module then sends an A/C request message over the Medium Speed Controller Area Network (MS-CAN) bus to the Instrument Cluster (IC), then from the IC through the High Speed Controller Area Network (HS-CAN) bus to the PCM.
Voltage is provided to the A/C clutch relay switch contacts. When the PCM energizes the relay, voltage is supplied to the A/C compressor clutch field coil. The A/C compressor clutch field coil is grounded.
The evaporator discharge air temperature sensor is used for A/C compressor cycling. An accurate evaporator discharge air temperature is critical for compressor engagement. The temperature measurement is used by the PCM to turn off the A/C compressor when the evaporator temperatures are cold enough to freeze the condensation.
When an A/C request is received by the PCM, the A/C compressor clutch will only be engaged through the A/C clutch relay if all of the following conditions are met:
- The A/C pressure transducer does not indicate excessively low or high refrigerant pressure. Refer to Specifications.
- The PCM does not detect excessively high engine coolant temperature.
- The PCM does not detect an ambient air temperature below 0°C (32°F).
- The PCM has not detected a Wide Open Throttle (WOT) condition.
- The HVAC module does not detect an evaporator discharge air temperature below 0°C (32°F).
This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- Evaporator discharge temperature sensor
- A/C pressure transducer
- PCM
- HVAC module
- A/C compressor clutch field coil
- A/C clutch relay
- A/C clutch air gap
- Battery Junction Box (BJB)
PINPOINT TEST K: THE AIR CONDITIONING (A/C) IS INOPERATIVE
NOTE: Before carrying out the following test, diagnose any HVAC, PCM or IC DTCs.
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 Fluorescent Dye Leak Detection.
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K1 CHECK THE A/C PRESSURE SENSOR (ACP_PRESS) PCM PID
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: ACP_PRESS PCM 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 PID similar?
Yes
Electronic Manual Temperature Control (EMTC) systems, GO to K3.
Dual Automatic Temperature Control (DATC) systems, GO to K2.
No
INSTALL a new A/C pressure transducer. TEST the system for normal operation. If the condition returns, GO to K11.
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K2 CHECK THE AIR CONDITIONING SWITCH STATUS (AC_SEL_SW) HVAC PID WITH THE A/C ON
- Enter the following diagnostic mode on the scan tool: AC_SEL_SW HVAC PID.
- Press the PANEL manual override button and press the A/C button (indicator on) on the HVAC module - DATC.
- Does the AC_SEL_SW HVAC PID read A/C?
Yes
GO to K3.
No
GO to K10.
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K3 CHECK THE A/C EVAPORATOR TEMPERATURE (EVAP_TEMP) HVAC PID
- Allow the vehicle exterior and interior to stabilize to the outside ambient temperature.
- Enter the following diagnostic mode on the scan tool: EVAP_TEMP HVAC PID.
- Does the EVAP_TEMP HVAC PID read similar to the ambient temperature?
Yes
GO to K4.
No
INSTALL a new evaporator discharge temperature sensor. TEST the system for normal operation. If the condition returns, GO to K10.
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K4 CHECK THE AIR CONDITIONING COMPRESSOR COMMANDED STATE (ACC_CMD) PCM PID WITH THE A/C ON
- Start the engine.
- Enter the following diagnostic mode on the scan tool: ACC_CMD PCM PID.
- Does the ACC_CMD PCM PID read ON?
Yes
GO to K6.
No
GO to K5.
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K5 CHECK THE AIR CONDITIONING COMPRESSOR CYCLING SWITCH (ACCS) PCM PID WITH THE A/C ON
- Enter the following diagnostic mode on the scan tool: ACCS PCM PID.
- Press the PANEL and A/C manual override buttons (A/C indicator ON) on the HVAC module - DATC or select MAX A/C on the HVAC module - EMTC.
- Does the ACCS PCM PID read ON?
Yes
GO to K11.
No
GO to K10.
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K6 CHECK THE VOLTAGE AT THE A/C COMPRESSOR CLUTCH FIELD COIL
- Ignition OFF.
- Disconnect: A/C Compressor Clutch Field Coil C100.
- Start the engine.
- Press the PANEL and A/C manual override buttons (A/C indicator ON) on the HVAC module - DATC or select MAX A/C on the HVAC module - EMTC.
- Measure the voltage between ground and A/C compressor clutch field coil C100-1, circuit CH401 (VT/WH), harness side.
- Is the voltage greater than 10 volts?
Yes
GO to K8.
No
CARRY OUT the A/C clutch relay component test.
CHECK the A/C clutch diode. INSTALL a new diode if necessary. If the relay tests OK, GO to K7.
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K7 CHECK THE A/C CLUTCH RELAY FOR VOLTAGE
- Ignition OFF.
- Disconnect: A/C Clutch Relay.
- Ignition ON.
- Measure the voltage between ground and the A/C clutch relay socket, circuit SBB13 (GY/RD).
- Is the voltage greater than 10 volts?
Yes
REPAIR circuit CH401 (VT/WH) for an open. TEST the system for normal operation.
No
VERIFY BJB fuse 13 (10A) is OK. If OK, REPAIR circuit SBB13 (GY/RD) for an open. TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short.
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K8 CHECK THE GROUND AT THE A/C COMPRESSOR CLUTCH FIELD COIL
- Ignition OFF.
- Measure the resistance between ground and A/C compressor clutch field coil C100-2, circuit GD120 (BK/GN), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to K9.
No
REPAIR circuit GD120 (BK/GN) for an open. TEST the system for normal operation.
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K9 CHECK THE A/C 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.
- Is the A/C compressor clutch air gap greater than 0.6 mm (0.024 in) ?
Yes
ADJUST the A/C compressor clutch gap. REFER to Air Conditioning (A/C) Clutch Air Gap Adjustment Adjustments. TEST the system for normal operation.
No
INSTALL a new A/C compressor clutch field coil. TEST the system for normal operation.
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K10 CHECK THE HVAC MODULE CONNECTION
- Inspect the module connectors for:
- corrosion.
- pushed-out terminals.
- damaged terminals.
- Connect and correctly seat all the HVAC module connectors.
- Clear the DTCs.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new HVAC module. TEST the system for normal operation.
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.
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K11 CHECK THE PCM CONNECTION
- Disconnect all the PCM connectors.
- Inspect the module connectors for:
- corrosion.
- pushed-out terminals.
- damaged terminals.
- Connect and correctly seat all the PCM connectors.
- Clear the DTCs.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new PCM. TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
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