Fuel Level Sensor

This procedure guides you through accessing and replacing the fuel level sensor in the fuel tank of a 2005 Dodge Viper, requiring lowering or removal of the fuel tank.

Warnings

Tools required

Parts

• Fuel level sensor / sending unit × 1 — Use OEM specification
• Fuel tank lock ring O-ring × 1 — Use OEM specification
• Fuel line O-rings × 2 — Use OEM specification

Preparation

1. Park vehicle on level, stable ground and engage parking brake.
2. Place wheel chocks at front wheels.
3. Disconnect negative battery cable to prevent electrical sparks.
4. Allow exhaust system to cool completely if vehicle has been running.
5. Gather all tools and new parts before beginning.

Procedure

1. 1

   Relieve Fuel System Pressure
   Remove the fuel filler cap to relieve tank pressure. Locate the fuel pump relay in the power distribution center under the hood and remove it. Attempt to start the engine; it should run briefly then stall as pressure is relieved. With the battery connected, crank the engine for a few seconds until it will not restart to ensure pressure relief. Then turn the ignition off, reinstall the relay, and disconnect the negative battery cable before proceeding.
   ⚠️Keep all ignition sources away from the work area during this and all subsequent steps.
2. 2

   Raise and Support Vehicle
   Raise the vehicle using a proper frame-contact lift or floor jack at the manufacturer-designated lift points, supporting on rated jack stands. Note the Viper is a low-clearance vehicle; verify the OEM lift points in the service manual before lifting. Support the vehicle securely on jack stands rated for the vehicle weight, positioned at the rear frame rails. Ensure the vehicle is stable before working underneath.
   ⚠️Never work under a vehicle supported only by a floor jack. Always use properly rated jack stands.
3. 3

   Drain Fuel Tank
   Position an approved fuel storage container under the fuel tank. Drain as much fuel as possible using an approved fuel extraction pump. Note the filler neck may contain an anti-siphon device; if siphoning through the filler neck is not possible, extract fuel through the fuel pump module opening or via the fuel supply line per the service manual. If the tank contains more fuel than can be safely stored, drain sufficient fuel to make the tank light enough to handle safely (target 2 gallons or less remaining). Label and store drained fuel in approved containers away from the work area.
   ⚠Gasoline expands when warm. Do not fill storage containers more than 95% full.
4. 4

   Disconnect Fuel Filler Tube
   Locate the fuel filler tube connection at the rear of the tank near the filler neck. Loosen the hose clamp securing the filler tube to the tank using a socket or flat-blade screwdriver. Slide the clamp back along the tube. Disconnect the filler tube from the tank; be prepared for residual fuel spillage. Use shop towels to catch any fuel.
   Torque spec

   Hose Clamps3 Nm (2 lb-ft)
5. 5

   Disconnect Fuel Tank Vent Lines
   Identify the vent lines connected to the top of the fuel tank (typically smaller diameter lines near the filler neck). Release the quick-connect fittings by pressing the release tabs or using the appropriate disconnect tool. Gently pull the lines free from the tank connections. Cap or plug open connections to prevent contamination.
   ℹ️Note the routing and position of vent lines for proper reinstallation.
6. 6

   Disconnect Fuel Supply and Return Lines
   Locate the fuel supply and return lines at the front of the fuel tank. These will be quick-connect fittings. Using the appropriate fuel line disconnect tool for the fitting size, release the locking mechanism and disconnect both lines from the fuel pump module. Be prepared for residual fuel spillage; use shop towels to absorb any fuel. Inspect the O-rings in the fittings and note their condition for replacement.
   ⚠Fuel under residual pressure may spray when lines are disconnected. Wear safety glasses and have towels ready.
7. 7

   Disconnect Fuel Pump Electrical Connector
   Locate the electrical connector for the fuel pump and level sensor assembly on top of the tank, typically near the center. Press the release tab on the connector and pull it straight off the fuel pump module. Secure the wiring harness out of the way to prevent damage during tank lowering.
   ℹ️Some connector designs have a secondary locking tab that must be released before the main connector can be separated.
8. 8

   Support and Lower Fuel Tank
   Support the tank with a transmission jack and wide wood block. Locate and remove the fuel tank retaining fasteners/straps as specified in the service manual for this vehicle; verify the exact mounting configuration and fastener count before removal. Carefully lower the jack while guiding the tank down, ensuring all lines and wiring are clear. Lower the tank sufficiently to access the top (approximately 8-12 inches of clearance).
   ⚠The tank may shift or tip when straps are released. Control the descent carefully and have an assistant help if available.
   Torque spec

   Mounting Bolts27 Nm (20 lb-ft)
9. 9

   Remove Fuel Pump Lock Ring
   With the tank lowered and accessible, clean debris from around the fuel pump module lock ring to prevent contamination from entering the tank. Using a brass punch or non-sparking tool and hammer, tap the lock ring in the loosening direction (typically counterclockwise; verify direction against the OEM service manual for this fuel module) using the tabs provided. Once loosened, unscrew the lock ring by hand and remove it. Set the lock ring and old O-ring aside.
   ⚠Use only non-sparking tools when working around fuel vapors. Do not use steel punches or hammers directly on the lock ring.
10. 10

    Remove Fuel Pump and Level Sensor Assembly
    Carefully lift the fuel pump module straight up and out of the tank opening. The fuel level sensor float arm is attached to the assembly and must be tilted to clear the tank opening without damage. Angle the assembly as needed to guide the float arm through the opening. Once clear, place the assembly on shop towels. Note the orientation of the assembly for reinstallation.
    ⚠The float arm is delicate and can be bent easily. Handle the assembly with care to avoid damage to the sensor.
    ℹ️Residual fuel will drain from the pump assembly. Have towels ready to absorb spillage.
11. 11

    Replace Fuel Level Sensor
    With the pump module removed, locate the fuel level sensor mounted to the pump assembly. Disconnect the internal electrical connector for the sensor. Remove the fasteners securing the level sensor to the pump module bracket (typically small clips or screws). Remove the old sensor and float arm assembly. Install the new fuel level sensor in the reverse order, ensuring the float arm moves freely through its full range of motion without binding. Reconnect the internal electrical connector.
    ℹ️Verify the new sensor matches the old unit exactly in terms of float arm length and mounting configuration before installation.
12. 12

    Install Fuel Pump Module
    Install the new O-ring onto the fuel tank opening, ensuring it seats properly in the groove. Carefully lower the fuel pump module back into the tank, tilting the assembly as necessary to guide the float arm through the opening without bending. Align the module to its original orientation, matching any alignment marks or tabs. Press the module down until it seats against the O-ring.
    ℹ️The module typically has an alignment feature to ensure correct positioning. Do not force the assembly if it does not seat easily.
13. 13

    Install Lock Ring
    Position the lock ring over the fuel pump module and thread it clockwise by hand until it contacts the module flange. Using a brass punch or non-sparking tool and hammer, tap the lock ring clockwise to tighten it securely. The lock ring should be tight enough that it cannot be turned by hand but does not require excessive force. Verify the O-ring has not shifted during installation.
    ⚠Do not overtighten the lock ring as this can damage the tank threads or compress the O-ring excessively.
14. 14

    Raise and Secure Fuel Tank
    Using the transmission jack or floor jack, carefully raise the fuel tank back into position in the vehicle. Align the tank mounting points with the strap locations. Reinstall the fuel tank retaining fasteners/straps and tighten the mounting bolts to the manufacturer-specified torque value for this vehicle (verify in the service manual before final tightening). Remove the jack from under the tank once the straps are secured.
    Torque spec

    Mounting Bolts27 Nm (20 lb-ft)
15. 15

    Reconnect Fuel Pump Electrical Connector
    Reconnect the electrical connector to the fuel pump module on top of the tank. Ensure the connector locks securely with an audible click. Verify the secondary locking tab (if equipped) is engaged. Tug gently on the connector to confirm it is seated properly.
16. 16

    Reconnect Fuel Lines
    Install new O-rings on the fuel supply and return line quick-connect fittings. Push the fuel lines onto the fuel pump module connections until they click into place. Tug on each line to verify it is locked. Ensure the lines are routed properly without kinks or interference with other components.
    ℹ️Always use new O-rings when reconnecting fuel lines. Reusing old O-rings can result in fuel leaks.
17. 17

    Reconnect Vent Lines and Filler Tube
    Reconnect the fuel tank vent lines to their connections on the tank, ensuring the quick-connect fittings lock securely. Push the fuel filler tube onto the tank connection and slide the hose clamp into position. Tighten the clamp to specification, ensuring a secure seal without crushing the rubber tube.
    Torque spec

    Hose Clamps3 Nm (2 lb-ft)
18. 18

    Lower Vehicle and Refill Fuel Tank
    Remove the jack stands and carefully lower the vehicle to the ground. Reconnect the negative battery cable. Add the previously drained fuel back into the tank through the fuel filler neck, plus additional fresh fuel to reach at least 1/4 tank level for testing. Install the fuel filler cap securely.
19. 19

    Prime Fuel System and Check for Leaks
    Turn the ignition key to the ON position (without starting the engine) for 5 seconds, then OFF. Repeat this cycle 3-4 times to allow the fuel pump to prime the system and build pressure. Inspect all fuel line connections, the fuel pump module lock ring, and the filler tube for any signs of fuel leakage. Wipe any residual fuel from previous spillage before checking.
    ⚠️Do not attempt to start the engine if any fuel leaks are detected. Repair all leaks before proceeding.

Reassembly

1. Installation is performed in reverse order of removal with the following notes:
2. Always install new O-rings on fuel line connections to prevent leaks.
3. Ensure the fuel pump module lock ring O-ring is properly seated before tightening the lock ring.
4. Torque all fasteners to specification using a calibrated torque wrench.
5. Route all fuel lines and vent lines in their original positions to avoid interference or chafing.

Verification

• With the fuel system primed, start the engine and allow it to idle for several minutes.
• Check the fuel gauge reading to verify it corresponds to the known fuel level in the tank.
• Monitor the fuel gauge as the engine runs to confirm the reading remains stable and accurate.
• Perform a final inspection under the vehicle for any fuel leaks at all connection points.
• Test drive the vehicle and observe the fuel gauge through various fuel levels to confirm proper sensor operation throughout its range.
• Verify no fuel smell is present in or around the vehicle, indicating a complete seal of the fuel system.

Related trouble codes on this vehicle

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

Chasing one of these codes and not sure which part is guilty? Ask a master mechanic about YOUR car →

More procedures for this vehicle