PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE

For a complete wiring diagram, refer to the Wiring Information.

1. NO RESPONSE

NOTE: For vehicle communication problems, use the scan tool to refer to the Network Review Screen. The screen depicts a high level view of the vehicle network. Fault and problem areas appear in red.

Does the scan tool display a Vehicle Network problem or NO RESPONSE condition?

Yes

(Refer to 29 - Non-DTC Diagnostics/Communication - Diagnosis and Testing) and perform the appropriate No Response diagnostic procedure.

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2. NO START

Does the vehicle have a NO START condition?

Yes

Check the vehicle for any DTCs, including Vehicle Theft Security related DTCs, which may cause a no-start condition.
If no DTCs are present that relate to a no-start condition, (Refer to 29 - Non-DTC Diagnostics/Drivability - Diesel - Diagnosis and Testing) for procedures related to Fuel and Starting systems.

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3. VEHICLE REPAIR HISTORY AND TSB(s)

1.	Check the vehicle repair history for repairs that may relate to the current condition.

2.	Inspect the vehicle for aftermarket accessories that may have been installed incorrectly.

3.	Check for any Technical Service Bulletins (TSBs) related to the condition or DTCs.

4.	If a TSB applies, follow the procedure outlined in the TSB.

Select the appropriate response for the condition that applies:

Performing a TSB procedure repaired the condition.

Test Complete.
Perform the PCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

A DTC is present, no TSB applies, or the TSB didn't repair the condition.

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No DTCs or conditions are present.

(Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure) and perform the INTERMITTENT DTC diagnostic procedure.

4. VEHICLE INSPECTION

Based on the diagnostic condition that applies, review the following list and perform any tests that relate to the condition:

If multiple DTCs are set in the PCM, review the wiring schematics for problems in any shared supply or ground circuits. (Refer to 29 - Non-DTC Diagnostics/Drivability - Diesel - Diagnosis and Testing) and perform the CHECKING THE PCM POWER AND GROUND CIRCUITS diagnostic procedure.
Inspect the air intake system and turbocharger related tubes for damage, restrictions, or poor connections.
Inspect the exhaust system and related tubes for damage, restrictions, or poor connections.
Remove and inspect the Air Filter for soiling or excessive dirt and debris which may cause an air flow restriction.
If the PCM detects and stores a DTC, the PCM also stores the environmental conditions under which the DTC was set.
Before erasing stored DTCs, record these conditions. Attempting to duplicate these conditions may assist when checking for an active DTC.

2.	Using the scan tool, Clear the stored DTCs.

3.	Attempt to duplicate the environmental conditions under which the DTC was set.

4.	Review the DTC When Monitored and Set Conditions. If possible, try to duplicate the vehicle conditions under which the DTC conditions will be monitored. Operate the vehicle under those conditions.

5.	Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the component and the module.

6.	If the DTCs are fuel or air handling system related, check the fuel level and quality.

Were any repairs made that corrected the DTC or condition?

Yes

Test complete.
Perform the PCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).

(Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure) and perform the appropriate diagnostic procedure.