GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2008 🢒 Vibe - FWD 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 Fuel Tank Leak Test

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Caution: Place a dry chemical (Class B) fire extinguisher near the area before performing a Fuel Tank Leak Check. Before removing the fuel tank for a suspected leak, make sure that the fuel pipes or the tubes are not leaking onto the tank. Once removed, make sure that the fuel is not leaking around the fuel sender O-ring. Failure to follow these precautions may result in personal injury.

Test Description

The fuel tank leak test is used to locate any fuel or fuel vapor escaping the fuel tank area. Fuel vapors escaping above the fuel level will be detected, if greater than the calibrated amount, when the evaporative emission (EVAP) diagnostics complete one test cycle. The malfunction indicator lamp (MIL) will illuminate after the EVAP diagnostics have failed 2 test cycles.

Diagnostic Aids
    • Operate the vehicle under the condition of the customer concern. Under high temperature conditions fuel vapors may increase to the point of EVAP canister vapor saturation. Fuel vapors would then be released into the atmosphere. Once the engine is running and the EVAP purge is enabled, all fuel vapor release would be eliminated.
    • Movement of the EVAP pipes or the fuel pipes may help find an intermittent condition.
    • If the fuel level is low, a liquid fuel leak may not be evident.

Reference Information

Special Tools

    •  J 41413-200 Evaporative Emissions System Tester (EEST)
    • J 41415-30 Fuel Tank Cap Adapter
    • J 41413-300 EVAP Cap and Plug Kit

System Testing
  1. Remove the fuel tank.

    2. Important: Refer to the J 41413-200 Evaporative Emissions System Tester (EEST) operation manual for detailed instructions.

  2. Connect the J 41413-200 to the fuel tank using the correct fitting from the J 41413-300 .
  3. Seal all the fuel tank openings with the J 41413-300
  4. Using the J 41413-200 introduce smoke into the fuel tank. Inspect for leaks in any of the following locations:
    5. • The fuel tank, the fill limiter vent valve, the pressure relief valve, and the grade vent valves
    • The fuel sender housing, the fuel sender seal, the fuel pipe, and the EVAP pipes
    • The fuel fill pipe and hose
    ⇒If smoke is observed, repair or replace the necessary component part or the fuel tank.
  5. Turn the nitrogen/smoke valve to nitrogen.
  6. Use the remote switch to introduce nitrogen and fill the EVAP system until the floating indicator stabilizes.
  7. Verify the flow meter's floating indicator position is stable and at or below the red flag for 5 minutes.
    8. ⇒If the floating indicator moves above the red flag, replace the fuel tank.

Repair Instructions

Fuel Tank Replacement