Pre-Diagnostic Troubleshooting Procedure

Pre-Diagnostic Troubleshooting Procedure

For a complete wiring diagram.

Test Step 1 - No Response

• 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 the appropriate BUS Communication test. Refer to => Electrical System DTC Based Diagnostics.

No

• Go to Test Step 2

Test Step 2 - No Start

Does the vehicle have a NO START condition?

Yes

• Check the vehicle for any DTCs, including vehicle theft security related DTCs, that may cause a no-start condition.

• If no DTCs are present that relate to a no-start condition, refer to => [ Fuel Delivery System Test ] Fuel Delivery System Test or to => [ Starting System Test ] Starting System Test.

No

• Go to Test Step 3

Test Step 3 - Vehicle Repair History and TSBs

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

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

• Check for any TSBs related to the condition or DTCs.

• 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 => [ PCM Verification Test ] PCM Verification Test.

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

• Go to Test Step 4

No DTCs or other conditions are present.

• Check for an intermittent DTC. Refer to => [ Checking for an Intermittent DTC ] Checking for an Intermittent DTC.

Test Step 4 - Vehicle Inspection


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 can result in personal injury or death.

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 the diagnostic procedure for Checking the PCM Power and Ground Circuits.

• Inspect the air intake system and, if equipped, any turbocharger related tubes for damage, restriction, or poor connection.

• Inspect the exhaust system and related tubes for damage, restriction, or poor connection.

• Remove and inspect the Air Filter for excessive dirt and debris which may cause an air flow restriction.

• When 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.

• With the scan tool, clear the stored DTCs.

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

• 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.

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

• If the DTCs 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. Refer to => [ PCM Verification Test ] PCM Verification Test.

No

• Refer to the diagnostic test procedure related to the DTC.