Have a dry chemical (Class B) fire extinguisher near the work area.

Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

1. Disconnect the negative battery calble.
2. Relieve fuel system pressure, refer to Fuel Pressure Relief Procedure .
3. Drain fuel tank, refer to Fuel Tank Draining Procedure .
4. Remove the fuel tank.

•	Refer to Fuel Tank Replacement (Tahoe/Yukon) .

•	Refer to Fuel Tank Replacement (Suburban) .

•	Refer to Fuel Tank Replacement (Extended Cab - Side Tank) .

•	Refer to Fuel Tank Replacement (Pick-up - Side Tank) .

•	Refer to Fuel Tank Replacement (Cab and Chassis - Rear Tank) .

•	Refer to Fuel Tank Replacement (Cab and Chassis - Side Tank) .

•	Refer to Fuel Tank Replacement .

5. Remove the fuel sender assembly, refer to Fuel Sender Assembly Replacement .

•	Whenever the fuel tank is cleaned, the fuel pump strainer must be inspected. If the strainer is contaminated, replace the strainer and inspect the fuel pump.

•	Inspect the fuel pump inlet for dirt and debris, if found replace the fuel pump. Refer to Fuel Sender Assembly Replacement .

6. Flush the fuel tank with hot water.
7. Pour the water out of the fuel sender assembly opening.
8. Rock tank to be sure that removal of water from tank is complete.

1. Inspect the in-line fuel filter for contamination.
2. Replace the fuel filter if the filter is plugged. Refer to In-Line Fuel Filter Replacement .

Clean the fuel lines by applying air pressure in the opposite direction of the fuel flow.

Notice: Do not fold or twist the strainer when installing the sending unit. This action restricts fuel flow.

1. Install the new strainer (if necessary) on the fuel sender assembly.
2. Install the fuel sender assembly with a new seal into the fuel tank
3. Install the fuel tank. Refer to the following:

•	Refer to Fuel Tank Replacement (Tahoe/Yukon) .

•	Refer to Fuel Tank Replacement (Suburban) .

•	Refer to Fuel Tank Replacement (Extended Cab - Side Tank) .

•	Refer to Fuel Tank Replacement (Pick-up - Side Tank) .

•	Refer to Fuel Tank Replacement (Cab and Chassis - Rear Tank) .

•	Refer to Fuel Tank Replacement (Cab and Chassis - Side Tank) .

•	Refer to Fuel Tank Replacement .

4. Disconnect the fuel feed line at the front of the vehicle.
5. Connect a hose to the fuel feed line at the front of the vehicle.
6. Insert the end of the hose into a 3.8 liter (one gallon) fuel can.
7. Connect the negative battery cable.
8. Install 23 liters (6 gallons) of clean fuel into the fuel tank.
9. Using the scan tool energize the fuel pump relay in order to operate the fuel pump, until 2 liters (1/2 gallons) of fuel flows into the fuel can. This will purge the fuel pump.
10. Install the fuel line at the front of the vehicle.
11. Check all the connections, for leaks.
12. Tighten all the hose clamps.

If fuel is leaking from the tank, the tank should be replaced. Make sure that the fuel lines are not leaking onto the tank.

1. Remove the fuel tank.
2. Drain the tank.
3. Plug all of the outlets.
4. Apply 7-10 kPa (1-1.5 psi) air pressure through the vent tube.
5. Test for leaks with a soap solution or by submersion.
6. Replace the tank if a leak is found.