Page 393 of 5267
U0001-CAN C BUS
For a complete wiring diagramRefer to Section 8W.
Page 395 of 5267

U0101-LOST COMMUNICATION WITH TCM
For a complete wiring diagramRefer to Section 8W.
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 PCM doesn’t receive a Bus Message from the Transmission Control Modulefor 7 consecutive seconds.
One trip failure. The circuit is continuously monitored.
Possible Causes
PCM FUSED IGNITION SWITCH OUTPUT CIRCUIT CHECK
BUS FAILURE OPEN OR SHORTED CONDITION
PCI BUS UNABLE TO COMMUNICATE WITH THE SCAN TOOL
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 the scan tool, erase DTCs.
Cycle the ignition key on and off several times. Leaving the ignition on forat least 20 seconds.
With the scan tool, read DTCs.
Does the DTC reset?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITIONSymptom (Diagnostic Procedure).
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.PCM FUSED IGNITION SWITCH OUTPUT CIRCUIT
Turn the ignition off.
Disconnect the C1 PCM 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 Miller Special Tool #8815
to perform diagnosis.
With a 12-volt test light connected to ground and with special tool
#8815 installed, probe the (F202), (F1), and (T751) Fused Ignition
Switch Output circuit.
Perform the above check with the Ignition key in the off lock position,
Ignition on, engine not running position, and during cranking.
Wiggle the related wire harness while probing the special tool with the
test light to try to interrupt the circuit.
Does the test light illuminate brightly?
Ye s>>
Go To 3
No>>
Repair the excessive resistance in the (F202), (F1), and (T751) Fused Ignition Switch (Off, Run, Start)
circuit. Inspect the related fuse, if the fuse is open check the circuit fora short to ground.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
Page 397 of 5267
U0121-LOST COMMUNICATION WITH ANTI-LOCK BRAKE MODULE
For a complete wiring diagramRefer to Section 8W.
Page 399 of 5267
U0141-LOST COMMUNICATIONWITH FRONT CONTROL MODULE
For a complete wiring diagramRefer to Section 8W.
Page 401 of 5267

U0155-NO CLUSTER BUS MESSAGE
For a complete wiring diagramRefer to Section 8W.
When Monitored:
Ignition key on and battery voltage greater than 10.4 volts.
Set Condition:
No messages received from the MIC (Instrument Cluster) for more than 20 seconds. One Trip Fault. Three
good trips to turn off the MIL.
Possible Causes
BUS CIRCUIT OPEN OR SHORTED
INSTRUMENT CLUSTER
PCM
Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - DIAGNOSIS AND TESTING for diagnostic
procedures and for further possible causes.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ACTIVE DTC
Ignition on, engine not running.
With the scan tool, erase DTCs.
Cycle the ignition key on and off several times.
With the scan tool, read DTCs.
Does the DTC reset?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITIONSymptom (Diagnostic Procedure).
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.COMMUNICATE WITH CLUSTER
With the scan tool, attempt to communicate with the Instrument cluster.
Can communication be established with the Instrument Cluster?
Ye s>>
Go To 3
No>>
Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - DIAGNOSIS AND TESTING for diag-
nostic procedures and for further possible causes.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
3.INSTRUMENT CLUSTER OPERATION
Start the engine
Allow the engine to idle.
Is the correct engine speed display in the instrument cluster (Tach)?
Ye s>>
Replace and program the Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Refer to the Instrument Category and perform the appropriate symptom.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
Page 402 of 5267
U0168-LOST COMMUNICATION WITH SKREEM
For a complete wiring diagramRefer to Section 8W.
Page 404 of 5267
U110C-NO FUEL LEVEL BUS MESSAGE RECEIVED
For a complete wiring diagramRefer to Section 8W.
Page 406 of 5267
U110E-LOST AMBIENT TEMPERATURE MESSAGE
For a complete wiring diagramRefer to Section 8W.