P0645

P0645-A/C CONTROL CIRCUIT/OPEN



- 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. Two Trip Fault. Three good trips to turn off the MIL.





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

1. A/C CLUTCH RELAY OPERATION
1. Ignition on, engine not running.
2. With a scan tool, actuate the A/C Clutch Relay.

NOTE: The DTC needs to be cleared before actuating the Relay, if the DTC is not cleared, the Relay may not be allowed to actuate.

Is the A/C Clutch Relay operating?

Yes

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Checking for an Intermittent DTC.

No

- Go To 2

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 PCM Verification Test. PCM Verification Test.

3. (A916) FUSED B+ CIRCUIT




1. Using a 12-volt test light connected to ground, probe the (A916) Fused B+ circuit in the connection.

Does the test light illuminate brightly?

Yes

- Go To 4

No

- Repair the open or short to ground in the (A916) Fused B+ circuit. Check and replace any open fuses.
- Perform the PCM Verification Test. PCM Verification Test.

4. (F202) FUSED IGNITION SWITCH OUTPUT CIRCUIT




1. Ignition on, engine not running.
2. Using a 12-volt test light connected to ground, probe the (F202) Fused Ignition Switch Output circuit in the connection.

Does the test light illuminate brightly?

Yes

- Go To 5

No

- Repair the open or short to ground in the (F202) Fused Ignition Switch Output circuit. Check and replace any open fuses.
- Perform the PCM Verification Test. PCM Verification Test.

5. (C13) A/C CLUTCH RELAY CONTROL CIRCUIT OPEN
1. Turn the ignition off.
2. Disconnect the C3 PCM harness connector.
3. Measure the resistance of the (C13) A/C Clutch Relay Control circuit from the relay connection to the PCM harness connector.

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 PCM Verification Test. PCM Verification Test.

6. PCM

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

1. 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 PCM Verification Test. PCM Verification Test.

No

- Replace and program the Powertrain Control Module.
- Perform the PCM Verification Test. PCM Verification Test.