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, Manual Climate Control System for schematic and connector information. Diagrams By Number
Refer to Wiring Diagram Set 55, Automatic Climate Control System for schematic and connector information. Diagrams By Number
Normal Operation
Under normal operation, when A/C is requested, a message is sent from the HVAC module over the Medium Speed Controller Area Network (MS-CAN) bus to the PCM. Ignition voltage is provided to the A/C clutch relay switch through circuit SBB24 (VT/RD). When the PCM energizes the relay, ignition voltage is supplied to the A/C clutch through circuit CH421 (GY). Ground is supplied for the A/C clutch through circuit GD120 (BK/GN).
This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- PCM
- HVAC module - Dual Automatic Temperature Control (DATC)
- HVAC module - Electronic Manual Temperature Control (EMTC)
- A/C evaporator discharge temperature sensor
- A/C pressure transducer
- A/C compressor clutch field coil
- A/C control relay
- A/C clutch air gap
PINPOINT TEST K: THE AIR CONDITIONING (A/C) IS INOPERATIVE
NOTICE: It is important to install relays in their correct position in the Battery Junction Box (BJB)). Installing a relay incorrectly may cause wiring shorts or damage to modules. While carrying out diagnostics on relays, have only one BJB relay removed at a time. Failure to follow these instructions may result in damage to the vehicle circuitry or to control modules.
NOTE: Some PCM DTCs may inhibit A/C operation. If any PCM DTCs are retrieved, diagnose those first. Refer to the PCM DTC Chart.
NOTE: Before carrying out the following test, diagnose any Instrument Cluster (IC) DTCs.
NOTE: When disconnecting and reconnecting the pressure transducer electrical connector, make sure that the connector-locking device is in place and that the locking device and connector are correctly and fully seated.
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 R-134a Manifold Gauge Set connected, compare the pressure readings of the R-134a Manifold Gauge Set and the ACP_PRESS PID.
- Are the pressure values of the R-134a Manifold Gauge Set and the ACP_PRESS PID similar?
Yes
GO to K2.
No
INSTALL a new A/C pressure transducer. TEST the system for normal operation.
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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 or select PANEL mode and press the A/C button (indicator on) on the HVAC module - EMTC.
- Does the AC_SEL_SW HVAC PID read PRESSED?
Yes
DATC, GO to K3.
EMTC, CARRY OUT the A/C Evaporator Discharge Temperature Sensor Component Test. If the sensor tests OK, GO to K4. Temperature Sensor - Evaporator Discharge
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 an ambient temperature above 16°C (60°F).
- 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 A/C evaporator discharge temperature sensor. TEST the system for normal operation.
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K4 CHECK THE AIR CONDITIONING CLUTCH (WAC/ACCR) PCM PID WITH THE A/C ON
- Enter the following diagnostic mode on the scan tool: WAC/ACCR PCM PID.
- Does the WAC/ACCR PCM PID read ON?
Yes
GO to K5.
No
GO to K11.
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K5 CHECK THE VOLTAGE AT THE A/C COMPRESSOR CLUTCH FIELD COIL
- Ignition OFF.
- Disconnect: A/C Compressor Clutch Field Coil C100.
- Ignition ON.
- Press the PANEL and A/C manual override buttons on the HVAC module - DATC or select MAX A/C on the HVAC module - EMTC.
- Measure the voltage between A/C compressor clutch field coil C100-1, circuit CH421 (GY), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to K6.
No
GO to K8.
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K6 CHECK THE GROUND AT THE A/C COMPRESSOR CLUTCH FIELD COIL
- Ignition OFF.
- Measure the resistance between A/C compressor clutch field coil C100-2, circuit GD120 (BK/GN), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to K7.
No
REPAIR circuit GD120 (BK/GN) for an open. TEST the system for normal operation.
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K7 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 average greater than 0.65 mm (0.030 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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K8 CHECK THE A/C CLUTCH RELAY FOR VOLTAGE
- Ignition OFF.
- Disconnect: A/C Clutch Relay.
- Ignition ON.
- Measure the voltage between the A/C clutch relay socket, circuit SBB24 (VT/RD) and ground.
- Is the voltage greater than 10 volts?
Yes
GO to K9.
No
VERIFY Battery Junction Box (BJB) fuse 24 (10A) is OK. If OK, REPAIR circuit SBB24 (VT/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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K9 CHECK CIRCUIT CH421 (GY) FOR AN OPEN
- Ignition OFF.
- Measure the resistance between the A/C clutch relay socket, circuit CH421 (GY) and A/C compressor clutch field coil C100-1, circuit CH421 (GY), harness side.
- Is the resistance less than 5 ohms?
Yes
CARRY OUT the A/C clutch relay component test. If the relay tests OK, GO to K11.
No
REPAIR circuit CH421 (GY) for an open. TEST the system for normal operation.
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K10 CHECK THE MODULE CONNECTION
- Carry out the HVAC Module Cold Boot Process. HVAC Module Cold Boot Process
- NOTE: DATC systems only.
- Carry out the HVAC Module - Dual Automatic Temperature Control (DATC) On-Demand Self Test. Alternate Diagnostic Methods - HVAC Module - Dual Automatic Temperature Control (DATC) Only
- Operate the system.
- Does the concern return?
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
- Clear the DTCs.
- Disconnect all of the PCM connectors.
- Check for:
- corrosion.
- pushed-out connectors.
- incorrectly seated connector.
- Connect and correctly seat all of the PCM connectors.
- Operate the system.
- Does the concern return?
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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