P0646

P0646-A/C CLUTCH CONTROL CIRCUIT LOW





For a complete wiring diagram Consult Diagrams/Electrical

- When Monitored:
With the ignition on and the A/C Clutch Relay command off.

- Set Condition:
The Engine Control Module (ECM) detects that the (C13) A/C Clutch Relay Control circuit is shorted to ground for 2.0 seconds.





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

Diagnostic Test

1. DTC IS ACTIVE
Ignition on, engine not running.
With the scan tool, Clear DTCs in the Engine Control Module (ECM).
With the scan tool, actuate the A/C Clutch Relay.
Monitor the scan tool for at least two minutes.
With the scan tool, select View DTCs.
Is the status Active for this DTC?

Yes

- Go To 2

No

- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure.Intermittent Condition

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




Turn the ignition off.
Disconnect the A/C Clutch Relay connector.
Disconnect the Engine Control Module (ECM) harness connector.
Measure the resistance between ground and the (C13) A/C Clutch Relay Control circuit in the A/C Clutch Relay connector.
Is the resistance below 1000 ohms?

Yes

- Repair the (C13) A/C Clutch Relay Control circuit for a short to ground.
- Perform the ECM Verification Test Ver. 1. Verification Tests

No

- Go to 3

3. (C13) A/C CLUTCH RELAY CONTROL CIRCUIT OPEN OR HIGH RESISTANCE




Measure the resistance of the (C13) A/C Clutch Relay Control circuit between the A/C Clutch Relay connector and the Engine Control Module (ECM) harness connector.
Is the resistance below 10.0 ohms?

Yes

- Go to 4

No

- Repair the (C13) A/C Clutch Relay Control circuit for an open circuit or high resistance.
- Perform the ECM Verification Test Ver. 1. Verification Tests

4. A/C CLUTCH RELAY
Connect the Engine Control Module (ECM) connector.
Install a substitute A/C Clutch Relay in place of the vehicle's A/C Clutch Relay.
Turn the ignition on.
With the scan tool, Clear DTCs.
With the scan tool, actuate the A/C Clutch Relay.
Monitor the scan tool for at least two minutes.
With the scan tool, select View DTCs.
Is the status Active for this DTC?

Yes

- Go to 5

No

- Replace the A/C Clutch Relay.
- Perform the ECM Verification Test Ver. 1. Verification Tests

5. ENGINE CONTROL MODULE (ECM)
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the A/C Clutch Relay and the Engine Control Module (ECM).
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals.
Search for any Technical Service Bulletins that may apply.
Were any problems found?

Yes

- Repair as necessary.
- Perform the ECM Verification Test Ver. 1. Verification Tests

No

- Replace the Engine Control Module (ECM).
- Perform the ECM Verification Test Ver. 1. Verification Tests