Fuel Level Sensor

This procedure replaces the fuel level sensor in the 2008 Dodge Viper by accessing the fuel tank from underneath the vehicle and removing the fuel pump module assembly.

Warnings

Tools required

Parts

• Fuel level sensor × 1 — Use OEM specification or Mopar part number for 2008 Viper
• Fuel pump module seal/O-ring × 1 — Use OEM specification

Preparation

1. Park vehicle on level ground and engage parking brake
2. Disconnect negative battery cable and wait 2 minutes to allow residual fuel system pressure to dissipate
3. Remove fuel filler cap to release any tank pressure
4. Relieve fuel system pressure by locating the fuel pump relay in the underhood fuse box, starting the engine, and allowing it to run until it stalls, then crank for 5 additional seconds
5. Raise vehicle using floor jack and support securely on jack stands at manufacturer-designated lift points
6. Ensure adequate working clearance underneath vehicle (minimum 24 inches recommended)

Procedure

1. 1

   Access fuel tank area
   Verify the fuel pump module access location for this vehicle; on the 2008 Viper access is typically through a service panel (behind the seats or in the rear storage compartment) rather than from underneath the vehicle. Locate the fuel tank and its fuel pump module access. On the 2008 Viper the fuel pump/sending unit is accessed through a service access panel (behind the seats / under the rear storage area) rather than solely from underneath — verify the correct access point against the factory service manual before proceeding. Identify the fuel pump module access cover on top of the fuel tank. Clean the area around the fuel pump module to prevent debris from entering the tank during disassembly.
2. 2

   Disconnect fuel lines
   Locate the fuel supply line connected to the fuel pump module (note: this vehicle uses a returnless-style system, so verify the number of lines before disconnecting). Place a drain pan underneath to catch any fuel spillage. Using the appropriate fuel line disconnect tools, depress the tabs on the quick-connect fittings and pull the fuel lines straight off the module. Plug the lines with clean shop towels or caps to prevent contamination and further fuel loss.
3. 3

   Disconnect electrical connector
   Locate the electrical connector on top of the fuel pump module. Press the release tab and carefully pull the connector straight up to disconnect it from the module. Move the connector and harness aside to provide clearance for module removal.
4. 4

   Remove fuel pump lock ring
   Using a fuel pump lock ring tool or a brass punch and hammer, rotate the lock ring counterclockwise to release it. Confirm whether the ring is a threaded or cam-lock (bayonet) style for this vehicle before applying force. The lock ring has several tabs for engagement. Carefully remove the lock ring and set it aside. Note the orientation of any alignment marks for reinstallation.
5. 5

   Remove fuel pump module assembly
   Carefully lift the fuel pump module assembly straight up and out of the fuel tank opening. The module includes the fuel pump, fuel level sensor, and associated float arm assembly. Tilt the module as needed to clear the opening while keeping the float arm from catching on the tank walls. Be prepared for residual fuel to drain from the module into the drain pan. Place the module on a clean work surface.
6. 6

   Remove old fuel level sensor
   With the fuel pump module removed, locate the fuel level sensor attached to the side of the module housing. Identify the electrical connector that plugs into the module circuit board and disconnect it. Remove the fasteners or release the retaining clips/slide rails securing the sensor and float arm assembly to the module housing (verify exact retention method and count against factory service documentation). Carefully detach the sensor and float arm, noting the orientation and routing of the float arm for proper reinstallation.
7. 7

   Install new fuel level sensor
   Position the new fuel level sensor and float arm assembly onto the module housing in the same orientation as the original. Ensure the float arm moves freely and is not obstructed. Secure the sensor using the mounting fasteners, ensuring they are properly tightened. Connect the electrical connector to the module circuit board, ensuring it clicks into place securely.
8. 8

   Inspect and replace fuel pump seal
   Inspect the large O-ring seal that sits in the groove around the fuel tank opening. If the seal shows any signs of damage, cracking, or compression set, replace it with the new seal. Clean the sealing surface on the fuel tank thoroughly. Install the new or reused seal into the groove, ensuring it seats properly around the entire circumference.
9. 9

   Reinstall fuel pump module assembly
   Carefully lower the fuel pump module assembly into the fuel tank opening, tilting as necessary to clear the float arm and internal components. Align any index marks or tabs on the module with the corresponding features in the tank opening. Press the module down until it seats fully against the seal. Verify that the module is properly positioned before proceeding.
10. 10

    Install fuel pump lock ring
    Position the lock ring over the fuel pump module, aligning it with the threads on the fuel tank. Using the fuel pump lock ring tool or brass punch and hammer, rotate the lock ring clockwise until it is fully seated and tight. Do not overtighten, as this can damage the tank threads or deform the seal.
11. 11

    Reconnect electrical and fuel lines
    Reconnect the electrical connector to the fuel pump module, ensuring it clicks into place and the locking tab engages. Remove the plugs or towels from the fuel lines. Push the fuel supply and return lines onto their respective fittings on the module until they click into place. Tug gently on each line to verify secure connection.
12. 12

    Restore power and prime fuel system
    Lower the vehicle from jack stands. Reconnect the negative battery cable. Turn the ignition key to the ON position (without starting) for 2 seconds, then OFF. Repeat this cycle 3-4 times to allow the fuel pump to prime the system and pressurize the fuel lines. Check underneath the vehicle for any fuel leaks at the connections.

Reassembly

1. Reinstallation follows removal in reverse order
2. Always replace the fuel pump module O-ring seal to prevent leaks
3. Ensure all fuel line quick-connect fittings are fully seated and locked
4. Verify the fuel pump lock ring is properly tightened but not overtorqued

Verification

• Turn ignition to ON position (without starting) and listen for fuel pump operation for approximately 2 seconds
• Start the engine and verify it runs smoothly without hesitation or fuel starvation symptoms
• Check the fuel gauge on the instrument cluster to confirm it reads accurately and responds to fuel level changes
• Inspect all fuel connections underneath the vehicle for leaks while the engine is running
• Test drive the vehicle and monitor the fuel gauge for proper operation throughout the fuel range

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

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