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*INTAKE AIR SYSTEM PRESSURE TEST
Diagnostic Test
1.CHARGE AIR COOLER PRESSURE TEST
Loosen air inlet tube clamp at the turbocharger.
Remove the air filter housing and the inlet tube from the vehicle as an assembly.
Install the CAC Pressure Tester #9022 into the inner diameter of the turbocharger, securing it in place with the
supplied three-fingered band clamp, tighten tool clamp to 8n.m (72 in lbs).
NOTE: NEVER ATTEMPT TO START OR RUN THE VEHICLE AT ANY TIME DURING THIS TEST,ENGINE DAM-
AGE MAY OCCUR.
Fasten the safety chain around a solid surface behind the turbocharger. Warning: Never run CAC Pressure test
without the safety chain securely fastened.
Before attaching shop air to the pressure regulator verify that the regulator is at its lowest pressure setting (0 psi).
Attach an air supply to the regulator and slowly increase the pressure until the pressure gauge reads 20 psi.
WARNING: WARNING: Never apply more than 20 PSI.
Using a solution of soap and water spray the Turbocharger, Turbocharger wastegate, Charge Air Cooler Heat
Exchange and CAC Hoses while watching for leaks.
Before any attempt to repair the CAC system is made, its necessary to completely discharge the system. This can
be accomplished by turning the regulator knob counter-clockwise.
Allow for adequate time to pass before removing the CAC Pressure tester from the turbo charger inlet.
Position the Air Filter Housing over thethreemountingstudslocatedonthe inside front fender well and press down
firmly to lock housing into place.
Install Air Inlet Tube over the Turbocharger inlet and torque the band clampto35in.lbs.
View Repair
Repair
Te s t c o m p l e t e .
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Page 898 of 5267
U0001-CAN C BUS
For a complete wiring diagramRefer to Section 8W.
Page 899 of 5267

When Monitored:
Ignition run time is greater than 1 second. Battery voltage between 9 and 16volts. Engine run time greater
than 3 seconds.
Set Condition:
The ECM loses communication over the CAN C Bus circuit. The circuit is continuously monitored. One Trip
fault.
Possible Causes
CAN C BUS OPEN OR SHORTED CONDITION
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - DIAGNOSIS AND TESTING for diagnostic
procedures and for further possible causes.
Diagnostic Test
1.ACTIVE DTC
Ignition on, engine not running.
With a scan tool, read FCM (TIPM) DTCs.
Is the DTC active at this time?
Ye s>>
Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - DIAGNOSIS AND TESTING for diag-
nostic procedures and for further possible causes.
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
Page 900 of 5267
U0121-LOST COMMUNICATION WITH ANTI-LOCK BRAKE MODULE
For a complete wiring diagramRefer to Section 8W.
Page 901 of 5267
When Monitored:
Ignition run time is greater than 1 second. Battery voltage between 9 and 16volts. Engine run time greater
than 3 seconds.
Set Condition:
The ECM doesn’t receive an ABS message over the CAN C circuit for 7 consecutive seconds. The circuit is
continuously monitored. One Trip fault.
Possible Causes
CAN C BUS OPEN OR SHORTED CONDITION
ABS MODULE
TIPM
PCM
Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - DIAGNOSIS AND TESTING for diagnostic
procedures and for further possible causes.
Diagnostic Test
1.ACTIVE DTC
Ignition on, engine not running.
With a scan tool, read ECM DTCs.
Is the DTC active at this time?
Ye s>>
Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - DIAGNOSIS AND TESTING for diag-
nostic procedures and for further possible causes.
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
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U0141-LOST COMMUNICATION WITH TIP MODULE
For a complete wiring diagramRefer to Section 8W.
Page 903 of 5267
When Monitored:
Ignition run time is greater than 1 second. Battery voltage between 9 and 16volts.
Set Condition:
TheECMdoesn’treceiveaFCM(TIPM)message over the CAN C circuit for 7 consecutive seconds. The
circuit is continuously monitored. One Trip fault.
Possible Causes
CAN C BUS OPEN OR SHORTED CONDITION
FCM (TIPM)
ECM
Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - DIAGNOSIS AND TESTING for diagnostic
procedures and for further possible causes.
Diagnostic Test
1.ACTIVE DTC
Ignition on, engine not running.
With a scan tool, read ECM DTCs.
Is the DTC active at this time?
Ye s>>
Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - DIAGNOSIS AND TESTING for diag-
nostic procedures and for further possible causes.
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
Page 904 of 5267

U1403-IMPLAUSIBLE FUEL LEVEL SIGNAL RECEIVED
For a complete wiring diagramRefer to Section 8W.
When Monitored:
Ignition on.
Set Condition:
The fuel volume message the ECM is receiving is implausible. The circuit iscontinuously monitored. One Trip
fault.
Possible Causes
CAN B OPEN OR SHORTED
CLUSTER MODULE
TOTALLY INTEGRATED POWER MODULE (TIPM)
ECM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Theory of Operation
The Totally Integrated Power Module isn’t receiving a fuel volume signal over CAN B from the Cluster Module. The
TIPM has to send the PCM a fuel volume signal over CAN C. The signal the TIPM sendsoverCANCisimplau-
sible.
Diagnostic Test
1.ACTIVE DTC
Ignition on, engine not running.
With a scan tool read DTCs.
Is the DTC active at this time?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.CAN B BUS HARDWARE DTCS ALSO ACTIVE
With a scan tool check for DTCs in the FCM (TIPM).
Are any CAN B Hardware related DTCs active at this time?
Ye s>>
(Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - DIAGNOSIS AND TESTING) for the
appropriate diagnostic procedures.
Perform BODY VERIFICATION TEST – VER 1.
No>>
Replace and program the Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)