P0645

P0645-A/C CLUTCH RELAY CIRCUIT





For a complete wiring diagram Consult Diagrams/Electrical.

- When Monitored:
With the ignition on. Battery voltage greater than 10.4 volts.

- Set Condition:
An open or shorted condition is detected in the A/C Clutch control circuit. One Trip Fault. Three good trips to turn off the MIL.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview.

Diagnostic Test

1. A/C CLUTCH OPERATION
NOTE: The DTC must not be active for the actuator test to operate properly, clear all DTC before continuing.

Ignition on, engine not running.
With a scan tool in the Powertrain Actuators, actuate the A/C Clutch
Is the A/C Clutch operating?

Yes

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure.Intermittent Condition
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 2

2. A/C CLUTCH CONTROL OPERATION FROM THE PCM
Turn the ignition off.
Disconnect the TIPM C1 harness connector.
Turn the ignition on.
Using the scan tool in the Powertrain Actuators, actuate the A/C Clutch
With a 12-volt test light connected to battery voltage, probe the A/C Clutch Control circuit in the TIPM C1 harness connector.
Does the test light illuminate brightly and flash on and off?

Yes

NOTE: Before continuing, check the TIPM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.
If OK, replace the TIPM.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 3

3. (C28) A/C CLUTCH CONTROL CIRCUIT SHORTED TO BATTERY VOLTAGE




Stop the A/C Clutch actuation.
Turn the ignition off.
Disconnect the PCM C3 harness connector.
Turn the ignition on.
Measure the voltage of the (C28) A/C Clutch Control circuit at the TIPM C1 harness connector.
Does the voltmeter indicate voltage present?

Yes

- Repair the short to voltage in the (C28) A/C Clutch Relay Control circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 4

4. (C28) A/C CLUTCH CONTROL CIRCUIT OPEN




Turn the ignition off.

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

Measure the resistance of the (C28) A/C Clutch Control circuit from the TIPM harness connector to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?

Yes

- Go To 5

No

- Repair the open in the (C28) A/C Clutch Control circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

5. (C28) A/C CLUTCH CONTROL CIRCUIT SHORTED TO GROUND




Measure the resistance between ground and the (C28) A/C Clutch Control circuit in the TIPM C1 harness connector.
Is the resistance below 100 ohms?

Yes

- Repair the short to ground in the (C28) A/C Clutch Control circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 6

6. PCM

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.
Were there any problems found?

Yes

- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Replace and program the Powertrain Control Module.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test