Diagnostic Routine K
Diagnostic Routine K
Diagnostic Overview
The Air Conditioning (AC) Is Inoperative
Refer to Wiring Diagram Set 54 for schematic and connector information Electrical Diagrams.
Normal Operation and Fault Conditions
REFER to Controls and Compressor Cycling .
REFER to Air Conditioning (AC) Pressure Transducer .
REFER to Evaporator Temperature Sensor .
Visual Inspection and Diagnostic Pre-checks
- Inspect BJB (Battery Junction Box) fuse 27 (15A).
- Inspect the A/C (Air Conditioning) clutch relay.
Pinpoint Test
1. CHECK THE A/C (Air Conditioning) PRESSURE SENSOR (ACP_PRESS) PID (Parameter Identification)
1. Using a scan tool, view PCM (Powertrain Control Module) PIDs (Parameter Identifications).
2. With a manifold gauge set connected, compare the pressure readings of the manifold gauge set and the PCM (Powertrain Control Module) PID (Parameter Identification) ACP_PRESS.
Are the pressure values of the manifold gauge set and the PID (Parameter Identification) similar?
2. CHECK THE AIR CONDITIONING REQUEST SIGNAL (AC_REQ) PID (Parameter Identification) WITH THE A/C (Air Conditioning) ON
1. KOER (Key ON Engine Running).
2. Using a scan tool, view PCM (Powertrain Control Module) PIDs (Parameter Identifications).
3. Monitor the PCM (Powertrain Control Module) PID (Parameter Identification) AC_REQ.
4. Select MAX A/C on the HVAC (Heating, Ventilation, and Air Conditioning) module.
Does the PID (Parameter Identification) read YES?
3. CHECK THE VOLTAGE ON THE AIR CONDITIONING REQUEST CIRCUIT
1. Ignition OFF.
2. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) module C2357A.
3. Ignition ON.
4. Measure:
Is the voltage between 4.7 and 5.1 volts?
4. CHECK THE AIR CONDITIONING REQUEST CIRCUIT FOR AN OPEN
1. Ignition OFF.
2. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C2357A.
3. Measure:
Is the resistance less than 3 ohms?
5. CHECK THE AIR CONDITIONING COMPRESSOR COMMANDED STATE (ACC_CMD) PID (Parameter Identification) WITH THE A/C (Air Conditioning) ON
1. Using a scan tool, view PCM (Powertrain Control Module) PIDs (Parameter Identifications).
2. View the PCM (Powertrain Control Module) PID (Parameter Identification) ACC_CMD.
Does the PID (Parameter Identification) read ON?
6. CHECK THE A/C (Air Conditioning) CLUTCH RELAY FOR VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
1. Ignition ON.
2. Measure:
Is the voltage greater than 11 volts?
7. CHECK THE A/C (Air Conditioning) COMPRESSOR CLUTCH FIELD COIL VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
1. Disconnect: A/C (Air Conditioning) Clutch Relay.
2. KOER (Key ON Engine Running).
3. Connect a fused jumper wire:
Does the A/C (Air Conditioning) compressor clutch engage?
8. CHECK THE A/C (Air Conditioning) COMPRESSOR CLUTCH FIELD COIL VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
1. Ignition OFF.
2. Disconnect: A/C (Air Conditioning) Compressor Clutch Field Coil.
3. Measure:
Is the voltage greater than 11 volts?
9. CHECK THE A/C (Air Conditioning) COMPRESSOR CLUTCH FIELD COIL GROUND CIRCUIT FOR AN OPEN
1. Measure:
Is the voltage greater than 11 volts?
10. CHECK THE A/C (Air Conditioning) COMPRESSOR CLUTCH AIR GAP
1. Measure the A/C (Air Conditioning) compressor clutch air gap at 3 equally spaced locations between the clutch hub and the A/C (Air Conditioning) compressor clutch pulley.
Is the A/C (Air Conditioning) compressor clutch air gap greater than 0.6 mm (0.0236 in)?
11. CHECK FOR CORRECT BCM (Body Control Module) OPERATION
1. Ignition OFF.
2. Disconnect and inspect all the BCM (Body Control Module) connectors.
3. 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
4. Reconnect the BCM (Body Control Module) connectors. Make sure they seat and latch correctly.
5. Operate the system and determine if the concern is still present.
Is the concern still present?
12. CHECK FOR CORRECT HVAC (Heating, Ventilation, and Air Conditioning) MODULE OPERATION
1. Ignition OFF.
2. Disconnect and inspect all the HVAC (Heating, Ventilation, and Air Conditioning) module connectors.
3. 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
4. Reconnect the HVAC (Heating, Ventilation, and Air Conditioning) module connectors. Make sure they seat and latch correctly.
5. Operate the system and determine if the concern is still present.
Is the concern still present?
13. CHECK FOR CORRECT PCM (Powertrain Control Module) OPERATION
1. Ignition OFF.
2. Disconnect and inspect all the PCM (Powertrain Control Module) connectors.
3. 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
4. Reconnect the PCM (Powertrain Control Module) connectors. Make sure they seat and latch correctly.
5. Operate the system and determine if the concern is still present.
Is the concern still present?
