Page 744 of 5267

4.FUEL LIFT PUMP CONTROL CIRCUIT SHORTED TO EXTERNAL VOLTAGE
Using a voltmeter, measure the voltage between battery negative and the lift pump control circuit at the TPIM con-
nector.
Is the voltage greater than 1 volt?
No>>
Go To 5
Ye s>>
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)
5.FUEL LIFT PUMP CONTROL CIRCUIT SHORTED TO OTHER CIRCUITS
Using an ohmmeter, measure the resistance between the lift pump control circuit in the ECM connector and all other
circuits in the ECM connectors.
Is the resistance less than 10 Ohms?
Ye s>>
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)
No>>
Go To 6
6.FUEL LIFT PUMP CONTROL CIRCUIT SHORTED TO EXTERNAL VOLTAGE
Connect the ECM and TIPM connectors.
Using a back probing tool 6801, back probe the lift pump control circuit in from TIPM connector.
Toggle the lift pump actuator with the Electronic Service Tool.
Using a 12 volt test light connected to battery negative, check the lift pump circuit at the TIPM connector.
NOTE: The test light must illuminate brightly.
Compare the brightness to that of a direct connection to the battery.
Does the test light cycle on and off and illuminate brightly?
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)
Ye s>>
Go To 7
7.FUEL LIFT PUMP DRIVER CIRCUIT SHORTED TO OTHER CIRCUITS
Using a back probing tool, back probe the lift pump control circuit in the TIPM connector.
Toggle the lift pump actuator with the scan Tool.
Using a 12 volt test light connected to battery negative, check the lift pump control circuit at the TIPM connector.
NOTE: The test light must illuminate brightly.
Compare the brightness to that of a direct connection to the battery.
Does the test light cycle on and off and 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 TPIM
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Page 746 of 5267

When Monitored:
Whilethekeyison.
Set Condition:
The commanded signal to the fuel lift pump relay does not match the feedbacksignal from the fuel lift pump
relay.
Possible Causes
DAMAGED WIRING HARNESS
LIFT PUMP DRIVER CIRCUIT SHORTED TO GROUND
ECM
TIPM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.LIFT PUMP DRIVER CIRCUIT SHORTED TO GROUND
Turn the ignition on, engine off.
Disconnect the ECM and TIPM connectors.
NOTE: Check connectors - Clean/repair as necessary.
Using an ohmmeter, measure the resistance of the lift pump driver wire between the ECM connector and ground.
Is the resistance less than 10 Ohms?
Ye s>>
Fix or repair the wire harness.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 2
2.ECM
Turn Ignition off.
Connect the ECM and TIPM connectors.
Turn the ignition on, engine off.
Using a back probing tool 6801, back probe the lift pump logic pin in from TIPM connector.
Toggle the lift pump actuator with the Electronic Service Tool.
Using a 12 volt test light connected to battery negative, check the lift pump circuit at the TIPM connector.
NOTE: The test light must illuminate brightly.
Compare the brightness to that of a direct connection to the battery.
Does the test light cycle on and off and 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 747 of 5267
3.TIPM
Using a back probing tool 6801, back probe the lift pump power pin in from TIPM connector.
Toggle the lift pump actuator with the Electronic Service Tool.
Using a 12 volt test light connected to battery negative, check the lift pump circuit at the TIPM connector.
NOTE: The test light must illuminate brightly.
Compare the brightness to that of a direct connection to the battery.
Does the test light cycle on and off and 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 TPIM
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Page 751 of 5267

When Monitored:
With the key on.
Set Condition:
Voltage detected on the #2 sensor supply circuit is below a calibrated value.
Possible Causes
FAN CLUTCH ASSEMBLY
(K668) 5-VOLT SHORTED TO GROUND
(K668) 5-VOLT SUPPLY SHORTED TO ANOTHER CIRCUIT
FA N D T C
INTERMITTENT CONDITION
ECM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.FAN CLUTCH ASSEMBLY
Disconnect the Fan clutch harness connector.
NOTE: Check connectors - Clean/repair as necessary.
With the scan tool, read DTCs.
Did P0483 set?
Ye s>>
Replace the Fan clutch assembly.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 2
2.(K668) 5-VOLT SHORTED TO GROUND
Turn the ignition off.
Disconnect the ECM harness connector.
NOTE: Check connectors - Clean/repair as necessary.
Measure the resistance between the (K668) #2 5-volt supply (fan speed
sensor power) circuit in the sensor harness connector and battery neg-
ative.
Is the resistance greater than 100k Ohms?
Ye s>>
Go To 3
No>>
Repair the #2 (K668) 5-volt supply shorted to ground.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
Page 755 of 5267

When Monitored:
With the key on.
Set Condition:
Voltage detected on the #2 sensor supply circuit was above a calibrated value.
Possible Causes
FAN CLUTCH ASSEMBLY
(K668) 5-VOLT SHORTED TO VOLTAGE
INTERMITTENT CONDITION
ECM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.FAN CLUTCH ASSEMBLY
Disconnect the Fan clutch harness connector.
NOTE: Check connectors - Clean/repair as necessary.
With the scan tool, read DTCs.
Did P0483 set?
Ye s>>
Replace the Fan clutch assembly.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 2
2.(K668) 5-VOLT SHORTED TO VOLTAGE
Disconnect the ECM harness connectors.
Disconnect the Fan harness connector.
NOTE: Check connectors - Clean/repair as necessary.
Measure the voltage between the fan speed sensor (K668) 5-volt supply
circuit and battery negative.
Is the voltage greater than 1 volt?
Ye s>>
Repair the (K668) 5-volt supply shorted to voltage.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
No>>
Go To 3
Page 756 of 5267
3.ECM
Turn the ignition off.
Reconnect the ECM harness connectors.
Turn the ignition on.
Measure the voltage between the (K668) 5-volt supply circuit in the sen-
sor harness connector and battery negative.
Is the voltage greater than 6 volts?
Ye s>>
Replace the ECM.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
No>>
Refer to the INTERMITTENT CONDITION Symptom (Diag-
nostic Procedure). (Refer to 9 - ENGINE - DIAGNOSIS
AND TESTING)
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)