For 1990-2009 cars

Caution: Place a dry chemical (Class B) fire extinguisher nearby before performing any on-vehicle service procedures. Failure to follow these precautions may result in personal injury.

### 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

### Circuit/System Description

The fuel tank leak test is used to locate any fuel or fuel vapour escaping the fuel tank area. Fuel vapours escaping above the fuel level will be detected when the evaporative emission (EVAP) leak diagnostic test is completed.

### Diagnostic Aids

• | Operate the vehicle under the condition of the customer concern. Under high temperature conditions fuel vapours may increase to the point of EVAP canister vapour saturation. Fuel vapours would then be released into the atmosphere. Once the engine is running and the EVAP purge is enabled, all fuel vapour release would be removed.

• | 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.

### Circuit/System Verification

1. Verify that the fuel tank and the fuel pipes are not damage or leaking.

⇒ | If you located a condition, repair as necessary before continuing with diagnostic procedure.

2. Ignition ON, command the fuel pump relay ON with a scan tool. Verify that the fuel pipes are not leaking.

⇒ | If you located a condition, repair as necessary before continuing with diagnostic procedure.

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

3. Ignition OFF, install commercially available smoke machine.
4. Command the EVAP vent solenoid closed with a scan tool.
5. Follow manufactures instructions , connect the smoke machine.

⇒ | If a leak is located, repair as necessary.

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

6. Using the commercially available smoke machine introduce smoke into the EVAP system. Verify that there are no vapour 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.

⇒ | If a leak is observed, repair as necessary.