Diagnostic 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 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 Required
| • | GE 41415-50 Interrupted Thread Cap Adapter |
| • | J 41413-200 (J 41413-100) Evaporative Emissions System Tester (EEST) |
System Verification
Warning: Gasoline or gasoline vapors are highly flammable. A fire could occur if an ignition source is present. Never drain or store gasoline or diesel fuel in an open container, due to the possibility
of fire or explosion. Have a dry chemical (Class B) fire extinguisher nearby.
| • | Inspect the fuel tank and the fuel pipes for damage or external leaks. |
| • | 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. |
System Testing
Note: If the floating indicator registers any flow after stabilizing, a leak is evident.
- Turn OFF the ignition. Install the
J 41413-200 (J 41413-100) EEST
and the
GE 41415-50 Adapter
. Test for a fuel leak while the system is under pressure referring to the J 41413-210 Operation Manual.
Note: It may be necessary to partially lower the fuel tank.
- Using the
J 41413-200 (J 41413-100) EEST
and the 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 valves |
| • | The fuel tank modules and seals, the fuel pipe, and the EVAP pipes |
| • | The fuel tank pressure (FTP) sensor seal |
| • | The fuel fill pipe and hose |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
