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 749 of 5267

P0633-SKIM SECRET KEY NOT ENTERED
For a complete wiring diagramRefer to Section 8W.
When Monitored:
Whilethekeyison.
Set Condition:
TheSKIMsecretkeywasnotcalibratedintotheECM.
Possible Causes
IMPROPER IGNITION KEY IS BEING USED
SKIM DTC’S
SKIM NOT CALIBRATED PROPERLY
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.SKIM DTC’S
With the scan tool, read SKIM DTCs.
Are any SKIM DTC’s present?
Ye s>>
Repair all SKIM DTC’s first.
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.IMPROPER IGNITION KEY IS BEING USED
Verify that the proper ignition key is in the ignition lock on the steering column.
Are the proper keys being used?
Ye s>>
Go To 3
No>>
Use the proper key for the vehicle.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
3.SKIM NOT CALIBRATED PROPERLY
Using the scan tool, recalibrate the ECM with the proper SKIM secret key.
With the scan tool, erase DTCs.
Cycle the ignition switch from on to off to on.
With the scan tool, read DTCs.
Did the DTC reset?
No>>
Te s t C o m p l e t e .
Ye s>>
Verify information is correct and replace ECM.
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 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 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 764 of 5267

When Monitored:
With the key on.
Set Condition:
Voltage detected on the sensor supply is below a calibrated value.
Possible Causes
ECM
(F855) #1 5-VOLT SUPPLY SHORTED TO GROUND
(F855) #1 5-VOLT SUPPLY SHORTED
FUEL RAIL PRESSURE
A/C PRESSURE SENSOR
MAP SENSOR
CAMSHAFT POSITION SENSOR
INTERMITTENT CONDITION
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.ECM
Turn the ignition off.
Disconnect the ECM 60 pin harness connector.
NOTE: Check connectors - Clean/repair as necessary.
Turn the ignition on.
Measure the voltage between the Sensor (F855) #1 5-volt Supply and
the Sensor (K916) #1 Return pin at the ECM.
Is the voltage between 4.5 and 5.5 volts?
Ye s>>
Go To 2
No>>
Replace and program the ECM in accordance with the Ser-
vice Information.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
Page 766 of 5267

5.MAP SENSOR
While monitoring with the scan tool, disconnect the map sensor.
Is DTC P0652 set?
Ye s>>
Go To 6
No>>
Replace the MAP sensor.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
6.CAMSHAFT POSITION SENSOR
While monitoring with the scan tool, disconnect the Camshaft position sensor.
Is DTC P0652 set?
Ye s>>
Go To 7
No>>
Replace the Camshaft position sensor.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
7.(F855) #1 5-VOLT SUPPLY SHORTED
Measure the resistance between the (F855) #1 sensor supply circuit of
the ECM harness connector and all other circuits in both ECM harness
connectors.
Is the resistance greater than 100K Ohms?
Ye s>>
Refer to the INTERMITTENT CONDITION Symptom (Diag-
nostic Procedure). (Refer to 9 - ENGINE - DIAGNOSIS
AND TESTING)
No>>
Repair the shorted circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)