Test Description

WARNING: This page is about a different car, the 2004 GMC Sierra and 2004 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

4: This step tests for fuel leaks below the fuel tank fuel level.
5: This step tests for fuel vapors escaping above the fuel level in the fuel tank.

Fuel Tank Leak Test

Step	Action	Yes	No
1	Did you perform the Diagnostic System Check - Engine Controls?	Go to Step 2	Go to Diagnostic System Check - Engine Controls
2	CAUTION: 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. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information. Inspect the fuel tank and the fuel pipes for damage or external leaks. Did you find fuel leaking from the fuel tank?	Go to Step 6	Go to Step 3
3	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. Did fuel leak from the fuel pipes?	Go to Step 7	Go to Step 4
4	Turn OFF the ignition. Install the J 41413-200 Evaporative Emissions System Tester (EEST) and the J 41415-40 Fuel Tank Cap Adapter or the GE-41415-50 Interrupted Thread Fuel Tank Cap Adapter. IMPORTANT: If the floating indicator registers any flow after stabilizing, a leak is evident. Test for a fuel tank leak referring to the J 41413-210 Operation Manual. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information. Inspect for a fuel leak while the system is under pressure. Did fuel leak from the fuel tank?	Go to Step 6	Go to Step 5
5	Using the J 41413-200 and the J 41413-210 Operation Manual, introduce smoke into the evaporative emission (EVAP) system. IMPORTANT: It may be necessary to partially lower the fuel tank. Refer to Fuel Tank Replacement . Inspect for leaks in any of the following locations: The fuel tank, fill limiter vent valve, pressure relief valve and the grade vent valves-Refer to Fuel Tank Replacement . The fuel sender housing and fuel sender seal-Refer to Fuel Sender Assembly Replacement . The fuel tank pressure (FTP) sensor seal-Refer to Fuel Tank Pressure Sensor Replacement . The EVAP pipes-Refer to Evaporative Emission (EVAP) Hoses/Pipes Replacement - Canister/Fuel Tank . The fuel fill pipe and hose-Refer to Filler Tube Replacement . Did you find and correct the condition?	Go to Step 8	Go to Diagnostic Aids
6	Replace the fuel tank. Refer to Fuel Tank Replacement . Did you complete the repair?	Go to Step 8	-
7	Replace the leaking fuel pipe. Refer to Fuel Hose/Pipes Assembly Replacement . Did you complete the replacement?	Go to Step 8	-
8	Operate the system under the condition of the customer concern in order to verify the repair. Did you correct the condition?	System OK	Go to Step 2