Replace the Diesel Exhaust Fluid (DEF) injector on the selective catalytic reduction (SCR) system to restore proper DEF injection and emissions control.

Warnings

Tools required

Parts

• DEF injector × 1 — Use OEM Mopar specification
• DEF injector gasket/seal kit × 1 — Use OEM specification
• Exhaust flange gasket × 1 — If damaged during removal

Preparation

1. Ensure vehicle has been off for at least 2 hours to allow exhaust system to cool completely
2. Park vehicle on level surface and engage parking brake
3. Disconnect negative battery cable to prevent inadvertent DTC codes during repair
4. Raise and support vehicle on jack stands if additional clearance is needed
5. Place drain pan under work area to catch any residual DEF fluid

Procedure

1. 1

   Access the DEF injector
   Locate the DEF injector on the decomposition tube assembly near the SCR catalyst inlet. It is mounted on the driver side of the exhaust system, forward of the SCR catalyst. Remove any heat shields that may obstruct access to the injector mounting area.
   Torque spec

   Heat Shield Bolts10 Nm (7 lb-ft)
2. 2

   Disconnect electrical connector
   Press the locking tab on the DEF injector electrical connector and carefully pull the connector straight off the injector. Do not twist or bend the connector during removal. Inspect connector pins for corrosion or damage.
   ℹ️If connector is difficult to remove, gently wiggle while pulling. Do not use excessive force as the connector housing can crack.
3. 3

   Disconnect DEF supply line
   Using a 13mm wrench, loosen the DEF supply line fitting at the injector. Once loose, carefully unthread by hand and pull the line away from the injector. Allow any residual DEF to drain into the catch pan. Cap or plug the open line to prevent contamination.
   ⚠DEF will drain from the disconnected line. Keep drain pan positioned to catch fluid and prevent spillage on exhaust components.
4. 4

   Remove injector mounting hardware
   Remove the mounting bolts securing the DEF injector to the decomposition tube using a 10mm or 13mm socket (depending on model year hardware). Support the injector while removing the final bolt to prevent it from falling.
   Torque spec

   Mounting Bolts37 Nm (27 lb-ft)
5. 5

   Remove DEF injector
   Carefully pull the DEF injector straight out of the decomposition tube. There may be resistance from the sealing O-rings. Do not twist or rock excessively. Once removed, inspect the mounting bore for debris, carbon buildup, or damage.
   ⚠Do not allow any debris to fall into the open decomposition tube as this will contaminate the SCR system.
6. 6

   Clean mounting surface
   Use a wire brush or clean shop towel to remove any carbon deposits or residue from the injector mounting surface on the decomposition tube. Ensure the bore is clean and free of debris. Inspect the mounting threads for damage.
   ℹ️Temporarily cover the open bore with a clean shop towel while cleaning to prevent debris entry.
7. 7

   Prepare new DEF injector
   Remove the new DEF injector from packaging. Install new O-rings or seals from the gasket kit onto the injector body, ensuring they are properly seated in their grooves. Lightly lubricate the O-rings with DEF fluid or clean water (do not use petroleum-based lubricants).
   ⚠Do not use any petroleum-based lubricants on DEF system components. This will cause system contamination and failure.
8. 8

   Install new DEF injector
   Carefully align the new DEF injector with the mounting bore in the decomposition tube. Push the injector straight in until it is fully seated against the mounting surface. Ensure proper orientation of the electrical connector and supply line port.
   ℹ️The injector should slide in smoothly. If excessive force is required, remove and check for obstructions or misalignment.
9. 9

   Install mounting hardware
   Install the mounting bolts finger-tight, ensuring the injector remains properly seated and aligned. Once all bolts are started, torque the mounting bolts to specification in a cross-pattern to ensure even seating pressure.
   Torque spec

   Mounting Bolts37 Nm (27 lb-ft)
10. 10

    Reconnect DEF supply line
    Remove the cap or plug from the DEF supply line. Thread the supply line fitting into the injector by hand until snug, then tighten with a 13mm wrench. Do not overtighten as this can damage the fitting or injector body.
    ⚠Cross-threading will damage the aluminum injector body. Ensure fitting threads smoothly before applying wrench force.
11. 11

    Reconnect electrical connector
    Align the electrical connector with the injector terminals and push firmly until the locking tab clicks into place. Gently tug on the connector to verify it is fully locked.
    ℹ️Ensure no debris or moisture is present in the connector before installation.
12. 12

    Reinstall heat shields
    If heat shields were removed for access, reinstall them in reverse order of removal. Torque heat shield bolts to specification.
    Torque spec

    Heat Shield Bolts10 Nm (7 lb-ft)
13. 13

    Complete electrical reconnection
    Reconnect the negative battery cable. Ensure the connection is clean and tight. This will restore power to the vehicle systems.

Reassembly

1. Verify all electrical connectors are fully seated and locked
2. Check that all mounting hardware is torqued to specification
3. Ensure no tools or materials were left in the work area
4. Clean any spilled DEF from components with water

Verification

• Start the engine and allow it to reach operating temperature
• Using a scan tool, verify no DEF system fault codes are present
• Check for DEF leaks at the injector supply line connection while engine is running
• Verify the DEF system indicator light is not illuminated on the instrument cluster
• Perform a test drive and monitor DEF system operation through the scan tool
• Confirm DEF fluid level reading is stable and system is consuming DEF normally during operation

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