Pinpoint Test K: The Air Conditioning (A/C) Is Inoperative
WARNING: This page is about a different car, the 2010 Mercury Mariner and 2010 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
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 .
- 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?
- 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.
- 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.
- 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 .
- 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?
- 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.
Refer to COMPONENT TESTING -- GASOLINE MODELS for component testing.
CHECK the A/C clutch diode. INSTALL a new diode if necessary. If the relay tests OK, GO to K7 .
- 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 appropriate SYSTEM WIRING DIAGRAMS article to identify the possible causes of the circuit short.
- 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.
- 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 . TEST the system for normal operation.
- No: INSTALL a new A/C compressor clutch field coil. REFER to CLIMATE CONTROL . TEST the system for normal operation.
- 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. REFER to CLIMATE CONTROL . 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.
- Inspect the module connectors for:
- 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.