2014 Jeep Wrangler JK Factory Service Manual 28 - DTC-Based Diagnostics

P0645-A/C CONTROL CIRCUIT/OPEN

Special Tools: Click to display a list of tools used in this procedure

For a complete wiring diagram, refer to the Wiring Information.





Theory of operation

When the ignition switch is on, the Totally Integrated Power Module (TIPM) sends a 12 Volt signal to the Powertrain Control Module (PCM) on the A/C Clutch Relay Control circuit. The PCM grounds this signal to indicate a request for A/C Compressor Clutch operation.


Possible Causes

(C13) A/C CLUTCH RELAY CONTROL CIRCUIT OPEN
(C13) A/C CLUTCH RELAY CONTROL CIRCUIT SHORTED TO GROUND
TOTALLY INTEGRATED POWER MODULE (TIPM)
POWERTRAIN CONTROL MODULE (PCM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).


1. DTC IS ACTIVE



NOTE: If there are any ASD/Main Relay or system voltage DTCs present, diagnose those DTCs before proceeding with this test procedure.
1. Ignition on, engine not running.
2. With the scan tool, select View DTCs. Copy DTC and Freeze Frame information and clear DTCs.

NOTE: Active or pending DTCs may not allow A/C clutch actuation, make sure all DTCs are cleared before proceeding with this test procedure.
3. With the scan tool, actuate the A/C Compressor.
4. Monitor the scan tool for at least two minutes.
5. With the scan tool, select View DTCs.


Is the status Active for this DTC?

Yes


No


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

1. Turn the ignition off.
2. Disconnect the TIPM C1 harness connector.
3. Disconnect the PCM C1 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 the GPEC Diagnostic Adaptor to perform the diagnosis.

4. Connect the Adapter, GPEC Diagnostic 10436 .
5. Measure the resistance between ground and the (C13) A/C Clutch Relay Control circuit at the GPEC Adaptor.


Is the resistance below 1000 Ohms?

Yes


No


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

1. Measure the resistance of the (C13) A/C Clutch Control circuit between the TIPM C1 harness connector and the GPEC Adaptor.


Is the resistance below 5.0 Ohms?

Yes


No


4. TOTALLY INTEGRATED POWER MODULE (TIPM) ACTUATION

1. Reconnect the TIPM C1 harness connector.
2. Turn the ignition on.
3. Connect a jumper between ground and the (C13) A/C Clutch Relay Control circuit at the GPEC Adaptor.


NOTE: The A/C Compressor Clutch should engage when the (C13) A/C Clutch Relay Control circuit is jumped to ground.


Did the A/C Compressor Clutch engage when the (C13) A/C Clutch Relay Control circuit is jumped to ground?

Yes


No


5. TOTALLY INTEGRATED POWER MODULE (TIPM)

1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Totally Integrated Power Module (TIPM) 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 related connectors.
4. Perform any Technical Service Bulletins that may apply.


Were any problems found?

Yes


No


6. POWERTRAIN CONTROL MODULE (PCM)

1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Totally Integrated Power Module (TIPM) 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 related connectors.
4. Perform any Technical Service Bulletins that may apply.


Were any problems found?

Yes


No