3.PCI BUS UNABLE TO COMMUNICATE WITH THE SCAN TOOL
NOTE: Determine which modules this vehicle is equipped with before beginning.
NOTE: When attempting to communicate with any of the modules on this vehicle, the scan tool will display
1 of 2 different communication errors: a NO RESPONSE message or a BUS +/- SIGNALS OPEN MESSAGE.
Ignition on, engine not running.
Use the scan tool, attempt to communicate with the remaining control modules.
Was the scan tool able to communicate with one or more of the Modules?
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 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)
When Monitored:
Ignition on.
Set Condition:
The PCM gets an implausible signal over the CAN C circuit from the ABS Module. The circuit is continuously
monitored. One Trip fault.
Possible Causes
CAN C BUS CIRCUIT SHORTED
CAN C BUS CIRCUIT OPEN
ABS MODULE
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Theory of Operation
The ABS Module sends vehicle speed information over the CAN C Bus circuit tothe PCM.
Diagnostic Test
1.ACTIVE DTC
Ignition on, engine not running.
With a scan tool, read DTCs.
Is the U1412-IMPLAUSIBLE VEHICLE SPEED SIGNAL RECEIVED 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.U0001-NO COMMUNICATION ON THE CAN C BUS CIRCUIT IS ACTIVE
Continue reading DTCs.
Is the U0001-NO COMMUNICATION ON THE CAN C BUS CIRCUIT ACTIVE at this time?
Ye s>>
Refer to the Diagnostic Procedure for the U0001-NO COMMUNICATION ON THE CANCBUSCIR-
CUIT.
No>>
Go To 3
3.ABS MODULE IS ACTIVE ON THE CAN C BUS
With the scan tool, select ECU View.
Verify that the ABS Module active on the bus.
Is the ABS Module active on the bus?
Ye s>>
Go To 4
No>>
(Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - DIAGNOSIS AND TESTING) for No
Response diagnostic procedures.
Perform BODY VERIFICATION TEST – VER 1.
When Monitored:
Ignition on.
Set Condition:
The PCM gets an implausible signal over the CAN C circuit from the ABS Module. The circuit is continuously
monitored. One Trip fault.
Possible Causes
VEHICLE SPEED SENSOR FAULT ACTIVE IN ANTI-LOCK BRAKE MODULE
CAN C BUS CIRCUIT SHORTED
CAN C BUS CIRCUIT OPEN
ABS MODULE
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Theory of Operation
The ABS Module sends an implausible distance signal over the CAN C Bus circuit to the PCM.
Diagnostic Test
1.ACTIVE DTC
Ignition on, engine not running.
With a scan tool, read DTCs.
Is the U1417-IMPLAUSIBLE LEFT WHEEL DISTANCE SIGNAL RECEIVED 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.ABS MODULE IS ACTIVE ON THE CAN C BUS
With the scan tool, select ECU View.
Verify that the ABS Module active on the bus.
Is the ABS Module active on the bus?
Ye s>>
Go To 3
No>>
(Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - DIAGNOSIS AND TESTING) for No
Response diagnostic procedures.
Perform BODY VERIFICATION TEST – VER 1.
3.DTCS STORED OR ACTIVE IN THE ABS MODULE
Check for DTCs in the ABS Module.
Are any DTCs active or stored in the ABS Module?
Ye s>>
Refer to section 5 - BRAKES - ABS ELECTRICAL DIAGNOSTICS and perform the diagnostics for the
DTCs in the ABS Module.
Perform ABS VERIFICATION TEST – VER 1
No>>
Go to 4
When Monitored:
Ignition on.
Set Condition:
The PCM gets an implausible signal over the CAN C circuit from the ABS Module. The circuit is continuously
monitored. One Trip fault.
Possible Causes
VEHICLE SPEED SENSOR FAULT ACTIVE IN ANTI-LOCK BRAKE MODULE
CAN C BUS CIRCUIT SHORTED
CAN C BUS CIRCUIT OPEN
ABS MODULE
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Theory of Operation
The ABS Module sends an implausible distance signal over the CAN C Bus circuit to the PCM.
Diagnostic Test
1.ACTIVE DTC
Ignition on, engine not running.
With a scan tool, read DTCs.
Is the U1418-IMPLAUSIBLE RIGHT WHEEL DISTANCE SIGNAL RECEIVED 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.ABS MODULE IS ACTIVE ON THE CAN C BUS
With the scan tool, select ECU View.
Verify that the ABS Module active on the bus.
Is the ABS Module active on the bus?
Ye s>>
Go To 3
No>>
(Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - DIAGNOSIS AND TESTING) for No
Response diagnostic procedures.
Perform BODY VERIFICATION TEST – VER 1.
3.DTCS STORED OR ACTIVE IN THE ABS MODULE
Check for DTCs in the ABS Module.
Are any DTCs active or stored in the ABS Module?
Ye s>>
Refer to section 5 - BRAKES - ABS ELECTRICAL DIAGNOSTICS and perform the diagnostics for the
DTCs in the ABS Module.
Perform ABS VERIFICATION TEST – VER 1
No>>
Go to 4
Possible Causes
NO START PRE-TEST
POWERTRAIN FUSES OPEN
SECONDARY INDICATORS PRESENT
ENGINE MECHANICAL
(K342) ASD RELAY OUTPUT CIRCUITS OPEN
FUEL CONTAMINATION
Diagnostic Test
1.NO START PRE-TEST
NOTE: The following list of items must be checked before continuing with any no start tests.
The battery must be fully charged and in good condition. A low charged battery may produce invalid test results. If
the battery is low, charge the battery and then attempt to start the vehicleby cranking the engine for 15 seconds,
3 consecutive times.
This will allow any DTCs to set that may have been erased due to a dead battery.
Try to communicate with PCM if not able to communicate check fuses.
Make sure the Powers and Ground to the PCM are OK.
Make sure the PCM communicates with the scan tool and that there are no DTCs stored in the PCM memory. If the
PCM reports a No Response condition, refer to section 8 Electrical Electronic Control Module Electrical Diagnostics
for the proper tests.
Read the PCM DTCs with the scan tool. If any DTCs are present, they must be repaired before continuing with any
other No Start diagnostic tests. Refer to the Table of Contents for the related P-code that is reported by the PCM.
Make sure that the Bus is functional. Attempt to communicate with the Instrument Cluster and VTSS, If you are
unable to establish communications refer to 8 Electrical Electronic Control Module Electrical Diagnostics for the
proper Diagnostic procedures.
The Sentry Key Immobilizer System mustbe operating properly. Check for proper communication with the scan tool
and check for DTCs that may be stored in the Sentry Key Immobilizer Module (SKIM). Repair the DTC(s) before
continuing.
If no DTCs are found, using the scan tool, select Clear PCM (BATT Disconnect).
Crank the engine several times. Using the scan tool, read DTCs. If a DTC is present perform the DTC diagnostics
before continuing.
Were any problems found?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 2
2.OPEN FUSE
Check for any open fuses in the IPM or Junction Block that may be related to theNoStartcondition.
Are any of the fuses open?
Ye s>>
Replace the open fuse and check the related circuit(s) for a short to ground.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 3
*NO RESPONSE WITH A NO START CONDITION
For a complete wiring diagramRefer to Section 8W.
Possible Causes
(A919) PCM FUSED B+ CIRCUIT
PCM NO RESPONSE
(F202) (F1) (T751) PCM FUSED IGNITION SWITCH OUTPUT CIRCUITS
(Z130) (Z131) PCM GROUND CIRCUITS
CRANKSHAFT POSITION SENSOR
(F855) 5-VOLT SENSOR OPEN/SHORTED
(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
(F856) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
PCM
Diagnostic Test
1.(A919) PCM FUSED B+ CIRCUIT
NOTE: The scan tool and cable must be operating properly for the
resultsofthistesttobevalid.
NOTE: Make sure the ignition switch was on while trying to com-
municate with the PCM.
Turn the ignition off.
Disconnect the PCM harness connectors.
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.
Using a 12-volt test light connected to ground probe the appropriate ter-
minal of special tool #8815.
Does the test light illuminate brightly?
Ye s>>
Go To 2
No>>
Repair the open or short to ground in the (A919) Fused B+
circuit. Inspect and replace fuses as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.(F202), (F1), (T751) PCM FUSED IGNITION SWITCH CIRCUITS
Using a 12-volt test light connected to ground, probe the PCM Fused
Ignition Switch Output circuits in the appropriate terminals of special tool
#8815.
Does the test light illuminate brightly?
Ye s>>
Go To 3
No>>
Repair the (F202) (F1) (T751) Ignition Switch Output cir-
cuits. Inspect and replace fuses as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE
For a complete wiring diagramRefer to Section 8W.
Diagnostic Test
1.NO RESPONSE
Make sure the scan tool will communicate with the appropriate modules.
Are you currently experiencing a NO RESPONSE condition?
Ye s>>
The NO RESPONSE condition must be properly diagnosed before continuing.
Refer to the appropriate BUS Communication test in Section 8 ELECTRONIC CONTROL MODULES -
ELECTRICAL DIAGNOSTICS.
No>>
Go To 2
2.NO START
Is the customer complaint a NO START condition?
Ye s>>
Check the vehicle for any NO START related PCM DTC(s) or Vehicle Theft Security related DTC(s).
If no Theft related DTC(s) are present, refer to the Non DTC Diagnostic Procedures that relate to Fuel
and Starting.
No>>
Go To 3
3.VEHICLE HISTORY AND TSB(s)
Continue by reading PCM DTC(s) and record the related Freeze Frame data if any DTC(s) are present.
Whether or not any DTC(s) are present you will want to check the following items which may assist in repairing the
customers complaint successfully.
Check the vehicles repair history.
If the vehicle has a repair history that pertains to the customer’s currentcomplaint, review the repair.
Inspect the vehicle for any aftermarket accessories that may have been installed incorrectly.
Check for any TSB(s) related to the customer’s complaint or DTC(s).
If a TSB applies, follow the instructions per the TSB.
Choose the following scenario that best applies.
The TSB repaired the customers complaint.
Testing complete.
A DTC is present, no TSB applies, or the TSB didn’t repair the customers complaint.
Go To 4
No DTC(s) are present.
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.