Service Procedure
A. Testing Inlet Check Valve Operation (Smoke Test):NOTE:
Fuel level in the tank is not critical to perform this test.
1. Open the fill cap door and slowly remove the gas cap.
2. Raise the vehicle on an appropriate hoist using the proper lift points.
3. Disconnect the vent tube quick connect located next to the filler tube (Figure 1).
4. Using Miller Special Tool 9790-3, plug the vent tube on the fuel tank side of the quick connect fitting (Figure 2).
5. Disconnect the carbon canister vent tube quick connect fitting from the canister (Figure 3).
6. Connect the Smoke Machine Adapter (Special Tool 9790-2) to the canister vent tube quick connect fitting (Figure 4).
7. Connect the other end of the Smoke Machine Adapter (Special Tool 9790-2) to the black discharge hose on the Smoke Machine (Special Tool 8404 or 8404A).
8. Lower the vehicle.
9. Turn on the Smoke Machine (Special Tool 8404 or 8404A) and inject smoke into the canister vent tube, filling the fuel tank for approximately 30 seconds.
> If smoke comes out of the fuel filler tube, continue with Section "B" Replace the Fuel Tank.
> If no smoke comes out of the fuel filler tube, continue with Step 10 of this procedure.
10. Turn off the Smoke Machine.
11. Apply a small amount of engine oil to the rubber plunger located on the end of the Probe Tool (Special Tool 9790-1). This will aid in the insertion and removal of the tool.
12. Insert the probe tool filler tube adapter into the filler tube opening (Figure 5).
The filler tube adapter is part of the probe tool.
CAUTION:
To prevent tool damage the filler tube adapter must be installed before inserting the probe tool.
13. Insert the Probe Tool (Special Tool 9790-1) until the handle of the tool is bottomed against the filler tube adapter (Figure 6). This will open the fuel tank inlet check valve. A slight burst of pressure and smoke will indicate that the inlet check valve has been opened. Keep the probe tool fully inserted for five seconds.
NOTE:
You may feel some slight resistance when inserting or removing the tool. This is due to the probe tool making its way around the various bends in the filler tube. This is a normal condition.
14. In an attempt to get the inlet check valve to stick in the open position, slowly remove the probe tool from the filler tube.
15. Turn on the Smoke Machine (Special Tool 8404A) and begin injecting smoke into the tank through the canister vent tube.
16. Watch for smoke exiting the fuel filler tube opening:
> If no smoke is seen coming out of the fuel filler tube, the valve is working properly. Repeat Steps 13 through 16 a second time to verify that the valve is working properly. If no smoke comes out of the fill tube opening during both attempts, continue with Step 17 of this procedure.
> If smoke comes out of the fuel filler tube opening, the inlet check valve is defective. Continue with Section B - Replace the Fuel Tank.
17. Turn off and disconnect the Smoke Machine (Special Tool 8404A) from the canister vent line.
18. Connect the canister vent line to the carbon canister.
19. Remove the Vent Tube Plug (Special Tool 9790-3) installed in the vent tube and reconnect the vent tube quick connect.
20. Install the gas cap and close the fuel door.
21. Return the vehicle to the customer.
B. Replace the fuel Tank:
NOTE:
Fuel tank replacement is only required if the vehicle fails the "Smoke Test" performed in Section "A." Very few vehicles are expected to require fuel tank replacement.
WARNING:
The fuel system is under a constant pressure (even with the engine off). Before replacing the fuel tank, the fuel system pressure must be released.
1. Use the following procedure to release the fuel pressure from the fuel system:
a. Remove the fuel pump relay from the Power Distribution Center (PDC). To determine the location of the fuel pump relay, refer to the label on the underside of the PDC cover.
b. Start and run the engine until it stalls.
c. Attempt to restart the engine until it will no longer run.
d. Turn the ignition to the "OFF" position.
e. Install the fuel pump relay back into the PDC.
NOTE:
Do not turn the key to the "run" position until all repairs have been made. Turning the key to the "RUN" position will turn on the fuel pump and pressurize the fuel system.
CAUTION:
One or more Diagnostic Trouble Codes (DTC's) may have been stored in the Powertrain Control Module (PCM) due to the fuel pump relay removal. A diagnostic scan tool must be used to erase all DTC's.
2. Drain the fuel tank using the following procedure:
a. Raise the vehicle on a hoist.
b. If equipped, remove the fuel tank skid plate.
c. Thoroughly clean the area around the fuel filler fitting and rubber hose at the rear of the tank.
d. Loosen the clamp and disconnect the rubber fuel filler tube at the gas tank fitting (Figure 8).
e. Using an approved fuel storage tanker, drain the fuel tank through the fuel tube filler fitting on the fuel tank.
3. Support the fuel tank with a hydraulic transmission jack.
4. Remove the two fuel tank strap bolts and remove both tank support straps (Figure 9).
5. Carefully lower the fuel tank a few inches and disconnect the fuel pump module electrical connector located on the top of the tank.
6. Disconnect the fuel line quick connect at the fuel pump module.
7. Disconnect the Natural Vacuum Leak Detection (NVLD), On-board Refueling Vapor Recovery (ORVR), and Evaporative (EVAP) lines located at the front of the fuel tank.
8. Disconnect the NVLD electrical connector.
9. Continue to lower the tank for removal.
10. With the help of an assistant, remove the old tank from the hydraulic jack and set the tank on the floor.
11. Use the following procedure to remove the fuel pump module:
a. Note the rotational position of the module before attempting removal. An indexing arrow is located on the top of the module for this purpose (Figure 10).
b. Position Special Tool 9340 into the notches on the outside edge of the lock ring (Figure 10).
c. Install a 1/2 inch drive breaker bar to Special Tool 9340.
d. Rotate the breaker bar counter-clockwise to loosen the lock ring.
e. Remove the lock ring.
NOTE:
The module will spring up slightly when the lock ring is removed.
f. Lift the fuel pump module from the fuel tank.
CAUTION:
Be careful not to bend the float arm while removing the fuel pump module.
12. Discard the old tank using an environmentally safe method.
13. Remove the new fuel tank from its packaging.
14. Install a new seal into the fuel pump module opening.
15. Position the fuel pump module into the opening in the fuel tank.
16. Position the lock ring over the top of the fuel pump module (Figure 10).
17. Rotate the module until the embossed alignment arrow points to the center alignment mark.
NOTE:
The pump module must be indexed to prevent the fuel gauge float from contacting the side of the fuel tank. Also be sure the fuel fitting on the top of the pump module is pointing towards the driver's side of the vehicle.
18. Using Special Tool 9340 and a 1/2 inch breaker bar, tighten the lock ring (clockwise) until all seven notches have engaged (Figure 10).
19. Transfer the NVLD pump, canister and canister vent line located on the front of the old fuel tank to the new fuel tank.
20. Transfer the heat shields from the old tank to the new tank.
21. Place the fuel tank assembly onto the hydraulic jack.
22. Carefully raise the tank until positioned near the body.
23. Connect the EVAP, ORVR and NVLD hoses and electrical connector located at the front of the tank.
24. Connect the fuel pump module electrical connector located at the top of the tank.
25. Connect the fuel line quick-connect fitting to the pump module.
26. Connect the fuel fill tube while raising the fuel tank into position. Continue raising the fuel tank until it is positioned snug against the floor pan.
27. Install and position both fuel tank support straps (Figure 9).
28. Install the fuel tank strap retaining bolts and tighten bolts to 30 ft. lbs. (41 Nm).
29. Position and tighten the fuel filler tube hose clamps (Figure 8).
30. Connect the fuel tank vent hose located next to the fuel fill tube (Figure 8).
31. If equipped, install the fuel tank skid plate. Tighten the bolts to 30 ft. lbs. (41 Nm).
32. Lower the vehicle and refill the fuel tank with the fuel that was removed.
33. Start the engine and check for leaks at the fuel tank and pump module area.
34. Connect the StarSCAN diagnostic tool and check all modules for Diagnostic Trouble Codes (DTC's).
NOTE:
When the fuel pump relay was removed to release the fuel system pressure, a Diagnostic Trouble Code (DTC) may have been set. Some DTC's may cause the Malfunction Indicator Lamp to illuminate. Check all modules using "System View" from the "Home" screen, record the DTC's, and erase these DTC's prior to returning the vehicle to the customer. Erase any DTC's in the Powertrain Control Module only after all other modules have had their DTC's erased.