Page 758 of 5267

When Monitored:
When the ignition is on.
Set Condition:
When the signal from the A/C Clutch circuit output does not match the signalfrom the A/C Clutch feedback
Possible Causes
LOW VOLTAGE SUPPLY TO THE TIPM
A/C CLUTCH CIRCUIT OPEN
A/C CLUTCH CIRCUIT SHORTED TO GROUND
TIPM
ECM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.TIPM GROUND OPEN
Ignition on, engine not running.
Using a voltmeter, connect one voltmeter lead to Battery Positive and the other on TIPM ground.
Does the voltmeter show battery voltage?
Ye s>>
Go To 2
No>>
Fix or replace the open circuit in the Battery Return Circuit
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
2.LOOSE CONNECTION
Disconnect the ECM and TIPM connectors.
NOTE: Check connectors - Clean/repair as necessary.
Using an Ohmmeter, measure the resistance of the A/C Clutch signal wire between the TIPM and the ECM con-
nector..
Is the resistance less than 10 Ohms?
No>>
Fix or replace the harness.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Ye s>>
Go To 3
3.A/C CLUTCH CIRCUIT OPEN
Turn the ignition off.
Using an Ohmmeter, measure the resistance of the A/C Clutch signal wire between the TIPM connector and battery
negative.
Is the resistance greater than 100k Ohms?
Ye s>>
Go To 4
No>>
Fix or replace the harness.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Page 759 of 5267

4.FUSED BATTERY SUPPLY
Connect the ECM and TIPM connectors.
Ignition on, engine not running.
Using a back probing tool 6801, back probe the A/C clutch logic pin in the TIPM logic connector.
Usinga12volttestlightconnectedtobatterypositive,checkthetransmission logic circuit at the TIPM connector
while actuating the A/C clutch circuit with the Electronic Service Tool.
NOTE: The test light must illuminate brightly.
Compare the brightness to that of a direct connection to the battery.
Does the test light illuminate brightly?
Ye s>>
Go To 5
No>>
Replace the ECM.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
5.TIPM
Using a back probing tool, back probe the A/C clutch power pin from the TIPM power connector.
Using a 12 volt test light connected to battery positive, check the transmission power circuit at the TIPM connector
while actuating the A/C clutch circuit with the Electronic Service Tool.
NOTE: The test light must illuminate brightly.
Compare the brightness to that of a direct connection to the battery.
Does the test light illuminate brightly?
Ye s>>
Te s t c o m p l e t e .
Perform Intermittent Condition test. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)
No>>
Replace the TIPM.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Page 760 of 5267
P0647-HIGH VOLTAGE DETECTED AT THE A/C CLUTCH RELAY
For a complete wiring diagramRefer to Section 8W.
Page 761 of 5267

When Monitored:
When the ignition is on.
Set Condition:
When the signal from the A/C Clutch output does not match the signal from theA/C Clutch feedback.
Possible Causes
WIRING HARNESS OR CONNECTIONS
A/C CLUTCH CIRCUIT SHORTED TO EXTERNAL VOLTAGE
TIPM
ECM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.A/C CLUTCH CIRCUIT SHORTED TO EXTERNAL VOLTAGE
Ignition off.
Disconnect the ECM and TIPM connectors.
NOTE: Check connectors - Clean/repair as necessary.
Ignition on, engine not running.
Using a Voltmeter, measure the voltage of the A/C Clutch Control Circuit between the TIPM connector and battery
negative..
Is the voltage less than 1 volt?
Ye s>>
Go To 2
Ye s>>
Repair or Replace the wiring harness.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
2.ECM
Ignition off.
Connect the ECM and TIPM connectors.
Ignition on, engine not running.
Using a back probing tool 6801, back probe the A/C clutch control circuit inthe TIPM connector.
Using a 12 volt test light connected to battery positive, check the transmission control circuit at the TIPM connector
while actuating the A/C clutch circuit with the Electronic Service Tool.
NOTE: The test light must illuminate brightly.
Compare the brightness to that of a direct connection to the battery.
Does the test light illuminate brightly?
Ye s>>
Go To 3
No>>
Replace the ECM.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Page 762 of 5267
3.TIPM
Using a back probing tool 6801, back probe the A/C clutch power circuit in the TIPM connector.
Using a 12 volt test light connected to battery positive, check the transmission power circuit at the TIPM connector
while actuating the A/C clutch circuit with the Electronic Service Tool.
NOTE: The test light must illuminate brightly.
Compare the brightness to that of a direct connection to the battery.
Does the test light illuminate brightly?
Ye s>>
Te s t c o m p l e t e .
Perform Intermittent Condition test. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)
No>>
Replace the TIPM.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Page 777 of 5267
P1272-A/C CLUTCH CONTROL CIRCUIT 2 LOW
For a complete wiring diagramRefer to Section 8W.
Page 778 of 5267

When Monitored:
With the ignition on. Battery voltage greater than 10 volts. A/C Switch on.
Set Condition:
A shorted condition is detected in the A/C clutch relay control circuit. One Trip Fault. Three good trips to turn
off the MIL.
Possible Causes
(C3) A/C COMPRESSOR CLUTCH CONTROL CIRCUIT SHORTED TO GROUND
A/C COMPRESSOR CLUTCH
TIPM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.A/C COMPRESSOR CLUTCH OPERATION
Ignition on, engine not running.
With a scan tool under the PCM Actuators, actuate the A/C Clutch.
Is the A/C Clutch actuating?
Ye s>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 2
2.A/C CLUTCH CONTROL OPERATION FROM THE PCM
Turn the ignition off.
Disconnect the C2 TIPM harness connector.
Ignition on, engine not running.
Using the scan tool under the PCM Actuators, actuate the A/C Clutch.
With a 12-volt test light connected to ground, probe the (C13) A/C
Clutch Control circuit in the C2 TIPM harness connector.
Does the test light illuminate brightly and flash on an off?
Ye s>>
Go To 3
No>>
Perform the Diagnostic Procedure for P0645-A/C CLUTCH
CONTROL CIRCUIT. (Refer to 9 - ENGINE - DIAGNOSIS
AND TESTING)
Page 779 of 5267

3.(C3) A/C CLUTCH CONTROL OUTPUT CIRCUIT SHORTED TO GROUND
Turn the ignition off
Disconnect the C9 TIPM harness connector.
Disconnect the A/C Compressor Clutch harness connector.
Measure the resistance between ground and the (C3) A/C Clutch Con-
trol Output circuit at the A/C Compressor Clutch harness connector.
Istheresistancebelow100ohms?
Ye s>>
Repair the short to ground in the (C3) A/C Clutch Control
Output circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
4.A/C COMPRESSOR CLUTCH
Connect the C2 and C9 TIPM harness connectors.
Ignition on, engine not running.
Using the scan tool under the TIPM Actuators, actuate the A/C Clutch.
With a 12-volt test light connected to ground, probe the (C3) A/C Clutch
Control Output circuit at the A/C Compressor Clutch harness connector.
Does the test light illuminate brightly and flash on and off?
Ye s>>
Replace the A/C Compressor Clutch per Service Informa-
tion.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 5
5.TOTALLY INTEGRATED POWER MODULE
NOTE: Before continuing, check the TIPM harness connector terminals for corrosion, damage, or terminal
push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors.
Pay particular attention to all Power and Ground circuits.
Were any problems found?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Replace the Totally Integrated Power Module per Service Information.
Perform the BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES - STANDARD PROCEDURE)