P0645-A/C CLUTCH RELAY CIRCUIT SHORT TO GROUND

For a complete wiring diagram Refer to Section 8W

When Monitored:
With the ignition on and the ECM A/C Clutch Relay command off.
Set Condition:
The ECM does not detect voltage on the A/C Clutch Relay Control circuit for 0.5 second.

Possible Causes

INTERMITTENT CONDITION

FUSED ASD RELAY OUTPUT CIRCUIT OPEN

A/C CLUTCH RELAY

A/C CLUTCH RELAY CONTROL CKT OPEN

A/C CLUTCH RELAY CONTROL CIRCUIT SHORT TO GROUND

ECM

Diagnostic Test

1.A/C CLUTCH RELAY OPERATION

NOTE: If the ECM detects and stores a DTC, the ECM also stores the engine/vehicle operating conditions under which the DTC was set. Some of these conditions are displayed on the scan tool at the same time the DTC is displayed.

NOTE: Before erasing stored DTCs, record these conditions. Attempting to duplicate these conditions may assist when checking for an active DTC.

Is the A/C Clutch Relay clicking?

Yes

Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

Go To2

2.FUSED ASD RELAY OUTPUT CIRCUIT OPEN

Does the test light illuminate?

Yes

Go To3

Repair the Fused ASD Relay Output circuit for an open.
Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

3.A/C CLUTCH RELAY

Does the test light cycle on and off?

Yes

Replace the A/C Clutch Relay.
Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

Go To4

4.A/C CLUTCH RELAY CONTROL CIRCUIT OPEN

Is the resistance below 10.0 ohms?

Yes

Go To5

Repair the A/C Clutch Relay Control circuit for an open.
Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

5.A/C CLUTCH RELAY CONTROL CIRCUIT SHORTED TO GROUND

Is the resistance below 1000 ohms?

Yes

Repair the A/C Clutch Relay Control circuit for a short to ground.
Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

Go To6

6.ECM

If there are no possible causes remaining, view repair.

Repair

Replace and program the Engine Control Module in accordance with the Service Information.
Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).