Fuel System Diagnosis

NOTE:
Refer to the appropriate vehicle's Service Manual for details.

WARNING:
Observe all Service Manual precautions, warnings, and instructions while servicing the fuel system.

1. Using the Scan Tool, activate the fuel pump and listen for its operational sound. If the fuel pump operates, go to Step 2.

If the fuel pump does not operate, also go to Step 2.

2. Measure the supply voltage of the fuel pump according to instructions shown in the Service Manual. If the supply voltage is within specifications (8 volts or more), go to Step 3.

If the fuel pump supply voltage is not within specifications, inspect and/or repair the fuel pump wiring harness as outlined in Group 13 of the Service Manual.





3. Check for correct fuel pressure in the system. If the fuel pressure is within service manual specifications, conduct further diagnostic testing to determine the cause of the fuel starvation. Refer to Group 13 of the Service Manual for further instructions.

If the fuel pressure is not within specifications, go to Step 4.





4. Remove the fuel pump from the fuel tank and inspect the fuel pump filter. If the filter is clean, replace the fuel pump.

If the filter is dirty and clogged, replace it according to the following procedure. Also, check for contamination in the fuel tank. If necessary, clean the fuel tank according to instructions shown in Group 13 of the Service Manual.