This procedure replaces the fuel pump assembly in a 2015-2020 Ford F-150 with 3.5L EcoBoost engine by accessing the pump module through the bed access panel.

Warnings

Tools required

Parts

• Fuel pump module assembly × 1 — Motorcraft PFS-479 or equivalent
• Fuel pump module O-ring seal × 1 — Use OEM specification
• Fuel line quick-connect O-rings (if damaged) × 2 — Use OEM specification

Preparation

1. Park vehicle on level ground and engage parking brake
2. Ensure fuel tank is less than 1/4 full to minimize spillage. If tank is fuller, siphon or drive to reduce fuel level
3. Disconnect negative battery terminal and wait 2 minutes for system de-energization
4. Place fire extinguisher within immediate reach of work area
5. Lay down absorbent pads or towels to catch fuel spillage
6. Ensure work area is well-ventilated with no pilot lights, water heaters, or other ignition sources nearby

Procedure

1. 1

   Relieve fuel system pressure
   With battery already disconnected, start the engine attempt will fail (as intended). Turn ignition to ON position for 5 seconds, then OFF. Repeat 3 times to dissipate residual fuel rail pressure. Alternatively, locate fuel pump fuse (F33 in engine compartment fuse box), remove it, start engine and let it run until it stalls, then crank for 5 additional seconds.
   ⚠️Skipping this step will result in pressurized fuel spray when lines are disconnected.
2. 2

   Access fuel pump module
   Fold up rear seat bottom cushion on driver side. Locate the rectangular access panel cover on the bed floor under the seat area. Remove the access cover screws using appropriate socket. Carefully lift access panel and set aside. You should see the fuel pump module lock ring and fuel lines.
   ℹ️On some crew cab models, you may need to remove or fold the rear seat for better access.
3. 3

   Disconnect electrical connector
   Locate the fuel pump module electrical connector on top of the module. Press the release tab and carefully pull the connector straight up to disconnect. Move connector aside to prevent damage.
4. 4

   Disconnect fuel supply line
   Identify the fuel supply line (larger diameter) connected to the pump module. Using the appropriate size fuel line disconnect tool, insert the tool into the quick-connect fitting and push inward while pulling the fuel line away from the module. Be prepared for residual fuel spillage. Place disconnected line into fuel-safe container.
   ⚠Residual fuel will drain from the line. Have towels and container ready to catch approximately 100-200ml of fuel.
5. 5

   Disconnect fuel return line
   Locate the fuel return line (smaller diameter) and disconnect using the same procedure as the supply line. Use appropriate size disconnect tool, insert into fitting, and pull line away. Catch any residual fuel.
6. 6

   Remove fuel pump lock ring
   Using the fuel pump lock ring tool, engage the tool into the notches of the lock ring. Rotate counterclockwise to loosen. The lock ring may be tight due to corrosion or fuel residue. Once loosened, unscrew completely by hand and remove the lock ring. Set aside in clean area.
   ⚠Do not use hammer or punch to turn lock ring as this can damage the tank flange threads or create sparks.
7. 7

   Remove fuel pump module
   Carefully lift the fuel pump module assembly straight up and out of the fuel tank opening. Tilt the module slightly to angle the float arm and fuel level sender through the opening. Be aware that fuel will drain from the module reservoir. Keep module over absorbent pads or fuel-safe container. Once clear, place module on clean work surface with additional absorbent material underneath.
   ⚠The fuel level sender arm is fragile. Avoid bending or damaging during removal.
   ⚠Approximately 0.5-1.0 liters of fuel will drain from the module.
8. 8

   Inspect and clean tank opening
   Inspect the fuel tank opening and sealing surface for debris, corrosion, or damage. Clean the sealing surface with a lint-free cloth. Check the tank flange for cracks or damage. Inspect the old O-ring seal and discard it. Ensure no debris falls into the fuel tank during this process.
9. 9

   Prepare new fuel pump module
   Remove new fuel pump module from packaging. Install the new O-ring seal onto the pump module flange, ensuring it seats properly in the groove. Lubricate the O-ring lightly with clean gasoline or petroleum jelly to ease installation. Verify the fuel level sender float arm moves freely and is not damaged.
   ℹ️Never reuse the old O-ring seal as this will cause fuel leaks and potential fire hazard.
10. 10

    Install new fuel pump module
    Carefully lower the new fuel pump module into the fuel tank opening. Angle the float arm and sender to fit through the opening, then align the module so the orientation marks or arrow on the module aligns with the corresponding mark on the tank flange. Press the module down firmly to seat the O-ring against the tank flange. Ensure the module sits flush.
11. 11

    Install and torque lock ring
    Thread the fuel pump lock ring onto the tank flange by hand, turning clockwise. Once hand-tight, use the fuel pump lock ring tool to torque the lock ring to specification. Ensure the lock ring is fully seated and properly torqued to prevent fuel leaks.
    ⚠Proper torque is critical. Under-torquing will cause fuel leaks; over-torquing can damage tank threads.
12. 12

    Reconnect fuel lines
    Connect the fuel supply line (larger) to the corresponding fitting on the pump module. Push the line straight onto the fitting until you hear and feel a distinct click. Tug gently to verify it is locked. Repeat for the fuel return line (smaller). Verify both connections are secure.
    ⚠Incomplete connection will cause fuel leaks under pressure. Always verify the click and perform pull test.
13. 13

    Reconnect electrical connector
    Align the fuel pump module electrical connector and press down firmly until the locking tab clicks into place. Verify the connection is secure by gently pulling on the connector.
14. 14

    Reinstall access cover
    Position the access cover over the opening, ensuring it is properly aligned. Install the access cover screws and torque to specification in a cross pattern to ensure even sealing.

Reassembly

1. Return rear seat cushion to normal position
2. Reinstall fuel pump fuse if it was removed
3. Reconnect negative battery terminal
4. Do not start vehicle yet - proceed to verification steps

Verification

• Turn ignition to ON position (do not start) for 5 seconds, then OFF. Repeat 3 times to prime fuel system and pressurize lines
• Inspect all fuel line connections at pump module for leaks. Look for fuel drips or wetness. Smell for fuel vapor
• Check access panel area for fuel odor or wetness
• If no leaks are observed, start the engine and let it idle for 2 minutes
• Recheck all connections while engine is running. Any fuel leak requires immediate engine shutdown and repair
• Verify fuel gauge operates correctly and shows appropriate level
• Test drive vehicle and monitor for proper fuel delivery, no stalling, and no fuel odor in cabin
• After test drive, perform final inspection of all connections for leaks with engine off and cooled

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