Test Description

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis 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.

1: Perform this procedure to determine that no EVAP diagnostic DTC is present.
3: This test is to locate fuel leakage in the fuel lines.
4: This tests for fuel leaks below the fuel tank fuel level.
5: This test is to locate 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 Trouble Code (DTC) List
2	IMPORTANT: Before performing this procedure, place a dry chemical, class B, fire extinguisher near the work area. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information. Inspect the fuel tank and fuel pipes for damage or external leaks. Did you find fuel leaking from the fuel tank?	Go to Step 7	Go to Step 3
3	Turn ON the ignition, with the engine OFF. Command the fuel pump ON with a scan tool. Inspect for fuel leaking from the fuel pipes. Did fuel leak from the fuel pipes?	Go to Step 8	Go to Step 4
4	Install the J 41415-40 Fuel Tank Cap Adaptor. Connect the J 41413-200 Evaporative Emissions System Tester (EEST) to the J 41415-40 . Seal the EVAP system with a scan tool. IMPORTANT: Do not exceed 15 in H2O. Pressurize the fuel tank with the J 41413-200 . Did fuel leak from the fuel tank?	Go to Step 7	Go to Step 5
5	Maintain pressure in the fuel tank with the J 41413-200 . IMPORTANT: It may be necessary to partially lower the fuel tank. Refer to Fuel Tank Replacement (Pickup) or Fuel Tank Replacement (Cab/Chassis - Front) or Fuel Tank Replacement (Cab/Chassis - Rear) . With the J 41416 Ultrasonic Leak Detector, test for leaks above the fuel level in the following locations. The fuel tank, fill limiter vent valve, pressure relief valve and rollover valves Refer to Fuel Tank Replacement (Pickup) or Fuel Tank Replacement (Cab/Chassis - Front) or Fuel Tank Replacement (Cab/Chassis - Rear) . 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 vapor pipes Refer to Evaporative Emission (EVAP) Hoses/Pipes Replacement - Canister/Fuel Tank . The fuel fill pipe and hose If equipped with a rear tank, the fuel tank, fill limiter vent valve, pressure relief valve and rollover valves Refer to Fuel Tank Replacement (Pickup) or Fuel Tank Replacement (Cab/Chassis - Front) or Fuel Tank Replacement (Cab/Chassis - Rear) . If equipped with a rear tank, the fuel sender housing and fuel sender seal Refer to Fuel Sender Assembly Replacement . Did you locate a fuel leak?	Go to Step 6	Go to Diagnostic Aids
6	Repair the system as necessary. Did you complete the repair?	System OK	-
7	Replace the fuel tank. Refer to Fuel Tank Replacement (Pickup) or Fuel Tank Replacement (Cab/Chassis - Front) or Fuel Tank Replacement (Cab/Chassis - Rear) . Did you complete the replacement?	System OK	-
8	Replace the leaking fuel pipe. Refer to Fuel Hose/Pipes Replacement - Chassis (Pickup) or Fuel Hose/Pipes Replacement - Chassis (Cab/Chassis - Front) or Fuel Hose/Pipes Replacement - Chassis (Cab/Chassis - Rear) . Did you complete the replacement?	System OK	-