Complete removal and replacement of the diesel exhaust fluid (DEF) tank assembly, including draining the system, disconnecting lines and electrical connections, and installing a new tank.

Warnings

Tools required

Parts

• DEF tank assembly × 1 — Use OEM specification
• DEF tank mounting hardware kit × 1 — May be included with tank
• DEF supply line O-rings × 2 — Use OEM specification
• DEF return line O-rings × 2 — Use OEM specification

Preparation

1. Park vehicle on level ground and apply parking brake
2. Place wheel chocks behind front wheels
3. If DEF tank contains fluid, use a DEF transfer pump to remove as much fluid as possible through the fill neck (store in appropriate container for reuse or disposal)
4. Raise rear of vehicle and support securely on jack stands rated for vehicle weight
5. Remove driver side rear wheel for improved access
6. Disconnect negative battery cable to prevent electrical issues during connector removal

Procedure

1. 1

   Access DEF tank area
   Remove the driver side rear inner fender liner or splash shield to access the DEF tank mounting area. The tank is located forward of the rear axle on the driver side frame rail. Remove any heat shields or protective covers that may obstruct access to the tank mounting bolts.
2. 2

   Disconnect electrical connections
   Locate the DEF tank heater connector and the DEF level/quality sensor connector on top of the tank. Press the locking tabs and carefully disconnect both electrical connectors. Secure connectors away from work area to prevent contamination.
   ⚠Do not pull on wires; press connector release tabs firmly to avoid damaging terminals.
3. 3

   Disconnect DEF supply and return lines
   Position drain pan beneath the DEF line connections. The supply line connects to the tank sender unit on top of the tank, and the return line also connects nearby. Press the quick-connect release tabs and carefully separate the lines from the tank fittings. Expect residual DEF to drain. Immediately cap or plug all openings to prevent crystallization and contamination.
   ⚠DEF will drain from lines when disconnected. Ensure drain pan is properly positioned.
4. 4

   Disconnect vent line
   Locate the DEF tank vent line running from the top of the tank. Trace the line to ensure proper identification. Disconnect the vent line from the tank fitting by pressing the quick-connect release or loosening the clamp, depending on connection type. Cap the opening on the tank.
5. 5

   Support DEF tank
   Position a transmission jack or suitable support device under the DEF tank. The tank holds approximately 8 gallons and weighs approximately 70 lbs when full (even after draining, residual fluid remains). Raise the jack slightly to take the weight off the mounting bolts.
   ⚠️DEF tank is heavy and awkward. Ensure adequate support before removing mounting bolts to prevent tank from falling.
6. 6

   Remove tank mounting bolts
   Remove the DEF tank mounting bolts that secure the tank straps or mounting brackets to the frame rail. There are typically 4-6 mounting bolts depending on configuration. Keep track of all mounting hardware including any spacers or insulators. Once all bolts are removed, carefully lower the tank using the support jack.
   Torque spec

   Mounting Bolts37 Nm (27 lb-ft)
7. 7

   Remove DEF tank from vehicle
   With the tank fully lowered, carefully maneuver it out from under the vehicle. Be mindful of any remaining lines or wiring that may still be attached. Tilt and rotate the tank as needed to clear frame rails and suspension components. Place the old tank in a suitable area for disposal or core return.
8. 8

   Prepare new DEF tank for installation
   Unpack the new DEF tank and verify all components are included. Install new O-rings on the supply and return line fittings (if separate from tank). Ensure the tank sender unit, heater element, and all fittings are properly secured. Do not remove protective caps from fittings until ready to connect lines.
9. 9

   Install new DEF tank
   Position the new DEF tank on the support jack and carefully raise it into position under the vehicle. Align the tank mounting brackets with the frame rail mounting points. Ensure all lines and electrical connectors can reach their connection points without strain. Insert mounting bolts with any spacers or insulators in their original positions.
10. 10

    Torque tank mounting bolts
    Thread all mounting bolts by hand first to ensure proper alignment. Once all bolts are started, torque the mounting bolts in a cross pattern to ensure even clamping force. This prevents tank deformation and ensures proper support.
    Torque spec

    Mounting Bolts37 Nm (27 lb-ft)
11. 11

    Reconnect DEF lines
    Remove protective caps from tank fittings. Connect the DEF supply line first, then the return line to their respective fittings on top of the tank. Push quick-connect fittings firmly until they click into place. Gently pull on each line to verify proper connection. Connect the vent line to the tank fitting and secure.
    ℹ️Ensure quick-connect fittings are fully seated and locked. A partial connection will cause leaks and system faults.
12. 12

    Reconnect electrical connections
    Connect the DEF tank heater electrical connector and the DEF level/quality sensor connector. Press firmly until connector locks click into place. Ensure no DEF contamination is present on connector terminals.
13. 13

    Reinstall protective components
    Reinstall any heat shields, protective covers, or mounting hardware that was removed for access. Reinstall the inner fender liner or splash shield. Ensure all fasteners are properly secured.

Reassembly

1. Reinstall driver side rear wheel and torque lug nuts to specification
2. Lower vehicle from jack stands
3. Reconnect negative battery cable
4. Fill DEF tank with fresh diesel exhaust fluid through the fill neck (blue cap) behind fuel door
5. Do not overfill; DEF expands when frozen

Verification

• Start engine and verify no DEF warning lights are illuminated on instrument cluster
• Allow vehicle to run for 5 minutes and check all DEF line connections for leaks
• Inspect underneath vehicle for any DEF drips or wet spots around tank and fittings
• Verify DEF level gauge reads correctly on instrument cluster
• Clear any diagnostic trouble codes if DEF system was empty during installation
• Test drive vehicle and verify DEF system operates normally with no warning messages

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