For 1990-2009 cars

### 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.

### Test Description

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.

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)

• | GE-41415-50 Interrupted Thread Cap Adapter

### System Verification

1. Inspect the fuel tank and the fuel pipes for damage or external leaks.
2. Turn ON the ignition, with the engine OFF. Command the fuel pump relay ON with a scan tool. Inspect for fuel leaking from the fuel pipes.
3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

### System Testing

Important: Refer to the J 41413-200 operation manual for detailed instructions.

1. Turn OFF the ignition. Install the J 41413-200 and the GE-41415-50 .
2. Command the EVAP vent solenoid closed with a scan tool.
3. Turn the nitrogen/smoke valve to Nitrogen and test for a fuel leak while the system is under pressure.

⇒ | Verify there is no liquid fuel leak. if a leak is located repair as necessary.

Important: It may be necessary to partially lower the fuel tank.

4. Using the J 41413-200 introduce smoke into the EVAP system. Inspect for vapor leaks in any of the following locations:

• | 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 tank pressure (FTP) sensor seal

• | The fuel fill pipe and hose

⇒ | Verify there is no fuel vapor leak. If a leak is located, repair as necessary.