Replace the ABS hydraulic control unit (HCU) module, which controls anti-lock braking and electronic stability systems. Requires brake bleeding and system recalibration.

Warnings

Tools required

Parts

• ABS Hydraulic Control Unit (HCU) × 1 — Use OEM Mopar part number
• Brake line sealing washers × 6 — Copper washers for brake fittings

Fluids

• Mopar DOT 4 Brake Fluid — 2 qt

Preparation

1. Park vehicle on level surface and engage parking brake. Place wheel chocks behind rear wheels.
2. Disconnect negative battery terminal and wait 2 minutes for airbag system to discharge.
3. Remove brake fluid reservoir cap and use suction tool to remove as much old fluid as possible to minimize spillage.
4. Raise front of vehicle and support securely on jack stands at frame rails. Remove both front wheels.
5. Locate ABS module on driver side frame rail behind front wheel, forward of the engine.
6. Place drain pan under ABS module to catch brake fluid.
7. Have at least 2 quarts of fresh DOT 4 brake fluid and scan tool ready before disconnecting lines.

Procedure

1. 1

   Remove ABS module protective cover
   Remove the plastic protective cover over the ABS module by releasing the retaining clips or removing fasteners. On some models this may be integrated with the fender liner. Gain clear access to the module and all brake line connections.
2. 2

   Label and photograph brake line connections
   Take detailed photographs of all six brake line connections to the ABS module from multiple angles. Note the position of each line - there are four wheel circuits (LF, RF, LR, RR) plus two master cylinder lines. Incorrect reconnection will cause brake system malfunction.
   ⚠️Brake lines MUST be reconnected to their original ports. Cross-connection will cause brake failure.
3. 3

   Disconnect electrical connector
   Press the red locking tab on the ABS module electrical connector and disconnect it from the module. Move the harness aside to prevent brake fluid contamination.
4. 4

   Disconnect brake lines from ABS module
   Using appropriate line wrenches (10mm or 11mm depending on fitting), carefully loosen and remove all six brake lines from the ABS module. Work slowly to avoid rounding off fittings. Allow brake fluid to drain into catch container. Cap or plug open lines immediately to prevent contamination. Note and discard all copper sealing washers.
   ⚠Use only line wrenches, not standard open-end wrenches. Brake line fittings strip easily and replacement requires complete line replacement.
5. 5

   Remove ABS module mounting bolts
   Remove the three 10mm mounting bolts securing the ABS module to the bracket on the frame rail. Support the module while removing the final bolt as it weighs approximately 5 pounds and contains residual brake fluid.
   Torque spec

   Mounting Bolts31 Nm (23 lb-ft)
6. 6

   Remove old ABS module
   Carefully lower the old ABS module from its mounting position. Keep it upright and place in drain pan to catch any remaining fluid. Inspect the mounting bracket for damage or corrosion and clean mounting surfaces thoroughly.
7. 7

   Install new ABS module
   Position the new ABS module onto the mounting bracket, aligning all three bolt holes. Install the three mounting bolts finger-tight first to ensure proper alignment, then torque to specification in a star pattern.
   Torque spec

   Mounting Bolts31 Nm (23 lb-ft)
8. 8

   Connect brake lines with new sealing washers
   Install new copper sealing washers on all six brake line fittings (one on each side of each connection). Thread each brake line into its correct port on the ABS module by hand first to avoid cross-threading. Refer to your photographs to ensure correct port assignment. Once all lines are hand-started, use line wrenches to torque each fitting to specification.
   ⚠️Verify each line is connected to the correct port before tightening. Incorrect connections will cause brake failure.
   Torque spec

   Line Fittings23 Nm (17 lb-ft)
9. 9

   Reconnect electrical connector
   Connect the electrical harness to the ABS module, ensuring it clicks and locks securely. Verify the red locking tab is fully engaged.
10. 10

    Refill brake fluid reservoir
    Fill the brake fluid reservoir to the MAX line with fresh DOT 4 brake fluid. Keep the reservoir topped off throughout the bleeding process - never let it drop below the MIN line or air will enter the system.
    ⚠Monitor reservoir constantly during bleeding. Running the reservoir dry will require restarting the entire bleeding procedure.
11. 11

    Perform manual brake bleeding
    Bleed each wheel brake in this order: RR, LR, RF, LF. At each wheel, attach clear tubing to bleeder screw and submerge other end in clean brake fluid. Have assistant pump brake pedal 3-4 times and hold. Open bleeder screw, allow fluid to flow until clear and bubble-free, close bleeder screw, release pedal. Repeat until no air bubbles appear. Torque bleeder screws to specification. Refill reservoir after each wheel.
    Torque spec

    Bleeder Screw16 Nm (12 lb-ft)
12. 12

    Perform ABS automated bleeding procedure
    Connect diagnostic scan tool to vehicle OBD-II port. Reconnect battery negative terminal. Turn ignition to ON position (engine off). Navigate to ABS system functions and select 'ABS Bleeding' or 'HCU Bleeding' procedure. Follow scan tool prompts to cycle the ABS pump and valves. This will purge air trapped in the ABS module internal valves that cannot be removed by manual bleeding. Monitor brake fluid reservoir and refill as needed during this process.
    ⚠️Manual bleeding alone is NOT sufficient. The ABS module contains internal valves that require electronic activation to bleed properly.
13. 13

    Repeat manual bleeding after ABS cycling
    After ABS automated bleeding is complete, repeat the manual bleeding procedure at all four wheels in the same order (RR, LR, RF, LF) to remove any air that may have been pushed into the wheel circuits during pump cycling. Ensure firm, consistent brake pedal feel.
    Torque spec

    Bleeder Screw16 Nm (12 lb-ft)
14. 14

    Check for leaks and clear codes
    With engine off, pump brake pedal firmly 10-15 times and hold pressure. Inspect all six brake line connections at the ABS module for any signs of fluid seepage. Check bleeder screws as well. If any leaks are present, do not proceed. Use scan tool to clear any ABS fault codes that may have been stored during the procedure.
    ⚠️Any brake fluid leak is unacceptable. Even minor seepage will lead to complete brake failure.
15. 15

    Reinstall wheels and final inspection
    Reinstall both front wheels and torque lug nuts to specification in a star pattern. Lower vehicle to ground. Fill brake fluid reservoir to MAX line. Pump brake pedal repeatedly until firm pedal is achieved. Start engine and verify ABS warning light extinguishes after bulb check.
    Torque spec

    Wheel Lug Nuts156 Nm (115 lb-ft)

Reassembly

1. Reinstall ABS module protective cover and any fender liner components removed during access.
2. Double-check all brake line connections are torqued properly and show no signs of leakage.
3. Ensure brake fluid reservoir is filled to MAX line with fresh DOT 4 fluid and cap is secure.
4. Verify all tools and parts have been removed from wheel wells and under vehicle.

Verification

• Turn ignition to ON. Verify ABS warning light illuminates briefly then extinguishes. If light remains on, diagnose fault codes with scan tool.
• Start engine and verify brake pedal is firm with approximately 1-2 inches of free play. Pedal should not sink to floor.
• Perform low-speed brake test in safe area. Brakes should engage smoothly with no pulling to either side.
• Perform ABS function test on dry pavement at 15-20 mph by applying firm brake pressure. ABS pulsation should be felt if system is functioning.
• Re-inspect all brake line connections at ABS module after test drive. No fluid seepage is acceptable.
• Verify no ABS warning lights are illuminated after test drive. Re-scan for codes if any lights appear.
• Check brake fluid level after test drive and top off if needed. Monitor fluid level over next few days for any drops indicating leaks.

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