Diagnostic Procedures

Perform Diagnostic System Check - Engine Controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article.

NOTE: Before performing this procedure, place a dry chemical (class B) fire extinguisher near the work area.

Raise the vehicle. Inspect the fuel tank and fuel pipes for damage or external leaks. Did you find fuel leaking from the fuel tank? If yes, go to step 7. If no, go to next step.
Turn ON the ignition, with the engine OFF. With a scan tool, command the fuel pump ON. Inspect for fuel leaking from the fuel pipes. Did fuel leak from the fuel pipes? If yes, go to step 8. If no, go to next step.
Install the Fuel Tank Cap Adapter (J 41415-40). Connect the EVAP Pressure/Purge Diagnostic Station (J 41413) to the fuel tank cap adapter. With a scan tool, seal the EVAP system. DO NOT exceed 15 in. H2O. With the EVAP pressure/purge diagnostic station, pressurize the fuel tank. Did fuel leak from the fuel tank? If yes, go to step 7. If no, go to next step.
With the EVAP pressure/purge diagnostic station, maintain pressure in the fuel tank. The fuel tank may need to be partially lowered. With the Ultrasonic Leak Detector (J 41416), test for leaks above the fuel level in the following locations.
- The fuel tank, fill limiter vent valve, pressure relief valve and rollover valves.
- The fuel sender housing and fuel sender seal.
- The Fuel Tank Pressure (FTP) sensor seal.
- The EVAP vapor pipes.
- The fuel fill pipe and hose.
Did you locate a fuel leak? If yes, go to next step. If no, see DIAGNOSTIC AIDS .
Repair the system as necessary. After repairs, system is okay.
Replace the fuel tank. After repairs, system is okay.
Replace the leaking fuel pipe. After repairs, system is okay.