For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle

• | Review Strategy Based Diagnosis

• | Diagnostic Procedure Instructions

### 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 more 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 may then be released into the atmosphere. Once the engine is running and the EVAP purge is enabled, all fuel vapor release may 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 Required

• | GE-41415-50 Fuel Tank Cap Adapter

• | EN-41413-200 Evaporative Emissions System Tester

• | EN-41413-300 EVAP Cap and Plug Kit

For equivalent regional tools, refer to LINK

### Circuit/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 KR23A Fuel Pump Relay ON with a scan tool. Inspect for fuel leaking from the fuel pipes.

### Circuit/System Testing

Note: Refer to the EN-41413-200 Evaporative Emissions System Tester operation manual for detailed instructions.

1. Ignition OFF, install the EN-41413-200 Evaporative Emissions System Tester (J 41413-100) and the GE-41415-50
2. Command the Q13 Evaporative Emission (EVAP) Canister Vent Solenoid Valve 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.

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

4. Using the EN-41413-200 Evaporative Emissions System Tester and the EN 41413-210 Operation Manual, introduce smoke into the evaporative emission (EVAP) system. Inspect for leaks in any of the following locations:

• | The fuel tank, the fill limiter vent valve, the pressure relief valve, and the grade vent valve

• | The fuel sender housing, the fuel sender seal, the fuel pipes, and the EVAP pipes.

• | The B150 Fuel Tank Pressure Sensor seal

• | The fuel fill pipe and hose

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