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*INTAKE AIR SYSTEM PRESSURE TEST . . . 1588
U0001-CAN C BUS ....................... 1589
U0121-LOST COMMUNICATION WITH
ANTI-LOCK BRAKE MODULE.............. 1591
U0141-LOST COMMUNICATION WITH TIP
MODULE................................. 1593
U1403-IMPLAUSIBLE FUEL LEVEL SIGNAL
RECEIVED............................... 1595U1412-IMPLAUSIBLE VEHICLE SPEED
SIGNAL RECEIVED....................... 1596
U0141-LOST COMMUNICATION WITH ECU . 1598
U1421-IMPLAUSIBLE IGNITION KEY OFF
TIME RECEIVED.......................... 1600
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ENGINE - ELECTRICAL DIAGNOSTICS - DIESEL
DIAGNOSIS AND TESTING
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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.
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4.WIRE HARNESS INSPECTION
Clear the DTC(s).
Attempt to duplicate the customer complaint.
Whether the customer complaint can be duplicated or not, make a quick wire harness inspection related to the
DTC(s) that were previously cleared.
Check the Powertrain Control Module connectors, the suspected componentconnection, in-line connectors, wire
harness splices, PCM power and ground circuits, and any related fuses.
If the DTC(s) are fuel or air related, check the fuel level and quality.
Were any repairs made that fixed the customer’s complaint?
Ye s>>
Testing complete.
No>>
Refer to the diagnostic test procedure related to the DTC.
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POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL)
Diagnostic Test
1.POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL)
1. Clear the DTC before continuing.
2. Check if any of the following conditions exist.
3. The ECM has been disconnected or replaced.
4. The battery power has been disconnected.
5. If the ECM has been replaced, do the following:
6. For ABS and Airbag Systems: Action: Enter correct VIN and Mileage in ECM.Erase ABS and Airbag Module
codes.
NOTE: 7. If the Engine Control Module has been replaced and the correct VIN and mileage have not been
programmed, a DTC will be set in the ABS, Airbag Modules and SKIM module.
8. If the ECM has not been replaced, do the following.
9. Inspect the vehicles to ensure that all engine components are connected. Reassemble and reconnect compo-
nents as necessary.
10. Attempt to start the engine.
11. If the engine is unable to start, look for any Technical Service Bulletins that may relate to this condition. Return
to Symptom list if necessary.
12. If the there are no DTCs present and all components are functional, the repair is complete.
Are any DTC(s) present?
Ye s>>
Repair is not complete, refer to appropriate symptom.
No>>
Repair is complete.
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POWERTRAIN VERIFICATION TEST VER - 2 (DIESEL)
Diagnostic Test
1.POWERTRAIN VERIFICATION TEST VER - 2 (DIESEL)
1. Check if any of the following conditions exist.
2. The ECM has been disconnected or replace.
3. The Battery power has been disconnected.
4. If the PCM has been replaced, do the following:
NOTE: 5. If the Engine Control Module has been changed and the correct VIN and mileage have not been
programmed, a DTC will be set in the ABS and Airbag Module.
6. For ABS and Airbag Systems: Enter correct VIN and Mileage in the ECM. Erase ABS and Airbag Module codes.
7. If the ECM has been replaced, do the following.
8. If this verification procedure is being performed after a No Trouble Code repair, do the following.
9. Check to see if the initial symptom still exists. If the initial or another symptom exists, the repair is not complete.
Check all pertinent Technical Service Bulletins and return to the Symptomlist if necessary.
10. If this verification procedure is being performed after a Trouble Coderepair, do the following.
11. Connect the scan tool to the data link connector and erase trouble codes.
12. With the scan tool, reset all memory values.
13. If this test is for an A/C trouble code, ensure it is operating during thefollowing road test.
14. Drive the vehicle for at least five minutes, For some of the drive, go at least 64 km/h (40 MPH). At some point
stop the vehicle and turn the engine off for 10 seconds or more; then restartand continue. Ensure the transmission
shifts through all gears.
15. Upon completion of the road test, turn the engine off and read trouble codeswiththescantool.Ifatroublecode
has been set, return to the Symptom list and follow the path specified.
Is there any DTC(s) present?
Ye s>>
Repair is not complete, refer to appropriate symptom.
No>>
Repair is complete.
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POWERTRAIN VERIFICATION TEST VER - 4 (DIESEL)
1.POWERTRAIN VERIFICATION TEST VER - 4 (DIESEL)
1. Check if any of the following conditions exist.
2. The ECM has been disconnected or replace.
3. The Battery power has been disconnected.
4. Inspect the vehicle to ensure that all engine components are properly installed and connected. Reassemble and
reconnect components as necessary.
5. With the DRBIII
,eraseDTCs.
6. If the ECM has been replaced, perform steps 11 through 13, then continue with the verification.
7. If ECM has been changed and correct VIN and mileage have not been programmed, a DTC will be set in ABS
and Air bag modules. In addition, if vehicle is equipped with a Sentry Key Immobilizer Module (SKIM), Secret Key
data must be updated to enable start.
8. For ABS and Air Bag systems: Enter correct VIN and Mileage in ECM. Erase codes in ABS and Air Bag modules.
9. For SKIM theft alarm: Connect DRBIII
to data link conn. Go to Theft Alarm, SKIM, Misc. and place SKIM in
secured access mode, by using the appropriate PIN code for this vehicle. Select Update the Secret Key data. Data
will be transferred from SKIM to PCM
10. Turn the speed control ON (if equipped, cruise light will be on).
11. Depress and release the SET Switch. If the speed control did not engage,the repair is not complete. Check for
TSBs that pertain to speed control problem and then, if necessary, return to Symptom List.
12. Depress and hold the RESUME/ACCEL Switch. If the vehicle speed did not increase by at least 2 mph, the
repair is not complete. Check for TSBs that pertain to speed control problem and then, if necessary, return to Symp-
tom List.
13. Press and hold the COAST switch. The vehicle speed should decrease. If it did not decrease, the repair is not
complete. Check for TSBs that pertain to speed control problem and then, ifnecessary, return to Symptom List.
14. Using caution, depress and release the brake pedal. If the speed control did not disengage, the repair is not
complete. Check for TSBs that pertain to speed control problem and then, ifnecessary, return to Symptom List.
15. Bring the vehicle speed back up to 35 MPH.
16. Depress the RESUME/ACCEL switch. If the speed control did not resume the previously set speed, the repair
is not complete. Check for TSBs that pertain to speed control problem and then, if necessary, return to Symptom
List.
17. Hold down the SET switch. If the vehicle did not decelerate, the repair is not complete. Check for TSBs that
pertain to speed control problem and then, if necessary, return to SymptomList.
18. Ensure vehicle speed is greater than 35 mph and release the SET Switch. If vehicle did not adjust and set a
new vehicle speed, the repair is not complete. Check for TSBs that pertain to speed control problem and then, if
necessary, return to Symptom List.
19. Depress and release the CANCEL switch. If the speed control did not disengage, the repair is not complete.
Check for TSBs that pertain to speed control problem and then, if necessary, return to Symptom List.
20. Bring the vehicle speed back up above 35 mph and engage speed control.
21. Depress the OFF switch to turn OFF, (Cruise light will be off). If the speed control did not disengage, the repair
is not complete. Check for TSBs that pertain to speed control problem and then, if necessary, return to Symptom
List.
22. If the vehicle successfully passed all of the previous tests, the speedcontrol system is now functioning as
designed. The repair is now complete.
23. NOTE: OVERSHOOT/UNDERSHOOT FOLLOWING SPEED CONTROL SET.
24. If the vehicle operator repeatedly presses and releases the SET buttonwith their foot off of the accelerator
(referred to as
lift foot set), the vehicle may accelerate and exceed the desired set speed by up to 5 mph (8km/h).
25. It may also decelerate to less than the desired set speed, before finally achieving the desired set speed.
26. The Speed Control System has an adaptive strategy that compensates forvehicle-to-vehicle variations in speed
control cable lengths.
27. When the speed control is set with the vehicles operators foot off of theaccelerator pedal, the speed control
thinks there is excessive speed control cable slack and adapts accordingly.
28. If the
lift foot setsare continually used, a speed control overshoot/undershoot condition will develop.
29. To
unlearnthe overshoot/undershoot condition, the vehicle operator has to press and release the set button
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while maintaining the desired set speedusing the accelerator pedal (not decelerating or accelerating).
30. Then turning the cruise control switch to the OFF position (or press theCANCEL button if equipped) after wait-
ing 10 seconds.
31. This procedure must be performed approximately 10-15 times to completely unlearn the overshoot/undershoot
condition.
Did the Speed Control pass the above test?
Ye s>>
Repair is not complete, refer to appropriate symptom.
No>>
Repair is complete.