FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
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Pre-Diagnostic Troubleshooting Procedure






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

- Manufacturer Code Charts Perform the appropriate No Response diagnostic procedure.

No

- Go To 2

2. NO START

Does the vehicle have a NO START condition?

Yes

- Check the vehicle for any DTC(s), including Vehicle Theft Security related DTC(s), that may cause a no-start condition.
- If no DTC(s) are present that relate to a no-start condition, Symptom Related Diagnostic Procedures for procedures that relate to Fuel and Starting.

No

- Go To 3

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 TSB(s) related to the condition or DTC(s).
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. PCM Verification Test.

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

- Go To 4

No DTC(s) or conditions are present.

- Perform the CHECKING FOR AN INTERMITTENT DTC diagnostic procedure. Checking for an Intermittent DTC.

4. VEHICLE INSPECTION

WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.

1. Based on the diagnostic condition that applies, review the following list and perform any tests that relate to the condition:
2. If multiple DTCs are set in the PCM, review the wiring schematics for problems in any shared supply or ground circuits. Perform the diagnostic procedure for Checking the PCM Power and Ground Circuits. Checking the PCM Power and Ground Circuits.
3. Inspect the air intake system and related tubes for damage, restriction, or poor connection.
4. Inspect the exhaust system and related tubes for damage, restriction, or poor connection.
5. Remove and inspect the Air Filter for excessive dirt and debris which may cause an air flow restriction.
6. If the PCM detects and stores a DTC, the PCM also stores the environmental conditions under which the DTC was set.
7. Before erasing stored DTCs, record these conditions. Attempting to duplicate these conditions may assist when checking for an active DTC.
8. With the scan tool, Clear the stored DTC(s).
9. Attempt to duplicate the environmental conditions under which the DTC was set.
10. 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.
11. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the component and the module.
12. If the DTC(s) are fuel or air 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. PCM Verification Test.

No

- Perform the diagnostic test procedure related to the DTC.