P0645

P0645-A/C CLUTCH RELAY CIRCUIT





For a complete wiring diagram Refer to the Wiring Information.

- When Monitored:
With the ignition on. Battery voltage greater than 10 volts. A/C Switch on.

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





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. ACTIVE DTC
1. Start the engine.
2. Allow the engine to reach normal operating temperature.
3. Turn the A/C on.
4. With a scan tool, select View DTCs and record the related Freeze Frame data.

Is the DTC Active at this time?

Yes

- Go To 2

No

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition Test.

2. A/C CLUTCH RELAY RESISTANCE
1. Turn the ignition off.
2. Remove the A/C Clutch Relay from the IPM.
3. Measure the resistance of the A/C Clutch Relay Coil.

Is the resistance between 60 to 80 ohms?

Yes

- Go To 3

No

- Replace the A/C Clutch Relay.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

3. (F942) FUSED IGNITION SWITCH OUTPUT CIRCUIT




1. Ignition on, engine not running.
2. Using a 12-volt test light connected to ground, probe the (F942) Fused Ignition Switch Output circuit in the connection.

Does the test light illuminate brightly?

Yes

- Go To 4

No

- Repair the open or short to ground in the (F942) Fused Ignition Switch Output circuit. Check and replace any open fuses.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

4. (A917) FUSED B+ CIRCUIT




1. Using a 12-volt test light connected to ground, probe the (A917) Fused B+ circuit in the connection.

Does the test light illuminate brightly?

Yes

- Go To 5

No

- Repair the open or short to ground in the (A917) Fused B+ circuit. Check and replace any open fuses.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

5. (C13) A/C CLUTCH RELAY CONTROL CIRCUIT OPEN




1. Turn the ignition off.
2. Disconnect the C3 PCM harness connector.

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 PCM Pinout Box 8815 to perform diagnosis.

3. Measure the resistance of the (C13) A/C Clutch Relay Control circuit from the relay connection to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?

Yes

- Go To 6

No

- Repair the open in the (C13) A/C Clutch Relay Control circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

6. (C13) A/C CLUTCH RELAY CONTROL CIRCUIT SHORTED TO GROUND




1. Measure the resistance between ground and the (C13) A/C Clutch Relay Control circuit at the IPM.

Is the resistance below 5.0 ohms?

Yes

- Repair the short to ground in the (C13) A/C Relay Clutch Control circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 7

7. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the A/C Clutch Relay and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the A/C Clutch Relay and Powertrain Control Module connectors.
4. Search for any Technical Service Bulletins that may apply.

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.