This procedure covers the removal and replacement of the ABS pump/HCU (Hydraulic Control Unit) assembly on a 2012-2018 Jeep Wrangler JK with 3.6L V6 engine, including brake line disconnection, module replacement, and system bleeding.

Warnings

Tools required

Parts

• ABS Pump/HCU Assembly × 1 — Use OEM specification
• Brake line sealing washers × 1 — Replace all washers on disconnected lines
• Thread locker × 1 — Medium strength

Fluids

• Mopar DOT 4 Brake Fluid — 1 qt

Preparation

1. Park vehicle on level surface and set parking brake
2. Disconnect negative battery terminal and wait 2 minutes for airbag system to discharge
3. Remove engine cover if equipped
4. Clean area around brake fluid reservoir and ABS pump to prevent contamination
5. Have brake fluid catch containers ready beneath work area
6. Ensure scan tool is connected and can communicate with ABS module before beginning

Procedure

1. 1

   Access ABS pump assembly
   The ABS pump is located on the driver side of the engine bay, mounted to the frame rail near the master cylinder. Remove any air intake components or battery tray components as needed for access. On some models, removing the air box provides better access.
2. 2

   Relieve brake system pressure
   With ignition OFF, pump brake pedal 25-30 times until pedal becomes firm and remains high. This releases hydraulic pressure stored in the ABS accumulator (if equipped) and makes line removal safer.
3. 3

   Disconnect ABS pump electrical connector
   Locate the large electrical connector on the ABS pump assembly. Press the locking tab and carefully disconnect the wiring harness. Move the harness out of the work area to prevent brake fluid contamination.
4. 4

   Label and disconnect brake lines
   Using a line wrench to prevent rounding, carefully loosen each brake line fitting at the ABS pump. There are typically 4-6 lines. Label each line position with tape or take a photo for reference during reassembly. Position drip pans underneath. Immediately cap or plug open lines to prevent fluid loss and contamination.
   ⚠Use only a line wrench (flare nut wrench) on brake fittings. Regular wrenches will round off the soft brass/steel fittings.
   Torque spec

   Line Fittings23 Nm (17 lb-ft)
5. 5

   Remove ABS pump mounting hardware
   Remove the mounting bolts securing the ABS pump bracket to the frame rail or mounting surface. Support the pump assembly as you remove the final bolt. The assembly is relatively heavy and contains residual brake fluid.
   ⚠ABS pump assembly weighs approximately 8-10 lbs and will contain residual brake fluid. Support properly during removal.
   Torque spec

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

   Remove ABS pump assembly
   Carefully lift the ABS pump assembly out of the engine bay. Keep it level to minimize fluid spillage. Place in drip pan. Inspect the mounting bracket and mounting surface for corrosion or damage.
7. 7

   Prepare new ABS pump
   Remove new ABS pump from packaging. Verify all electrical connectors and brake port configurations match the original unit. Install new sealing washers on all brake line ports. Do not reuse old washers.
8. 8

   Install new ABS pump assembly
   Position the new ABS pump assembly onto the mounting bracket, aligning bolt holes. Install mounting bolts and tighten to specification in a cross pattern to ensure even seating.
   Torque spec

   Mounting Bolts31 Nm (23 lb-ft)
9. 9

   Reconnect brake lines
   Thread each brake line fitting into the correct port on the new ABS pump, referring to your labels or photos. Start all fittings by hand to prevent cross-threading. Using a line wrench, tighten each fitting to specification. Double-check each connection for proper seating.
   ⚠Cross-threading brake line fittings will result in leaks and require replacement of expensive components. Always start fittings by hand first.
   Torque spec

   Line Fittings23 Nm (17 lb-ft)
10. 10

    Reconnect electrical connector
    Plug the wiring harness connector into the ABS pump assembly. Ensure the locking tab clicks into place and the connection is fully seated.
11. 11

    Refill brake fluid reservoir
    Fill the brake fluid reservoir to the MAX line with fresh Mopar DOT 4 brake fluid. Keep the reservoir filled throughout the bleeding process. Never let it drop below the MIN line.
12. 12

    Perform manual brake bleeding
    Bleed all four wheel brake calipers in this order: right rear, left rear, right front, left front. At each wheel, attach bleeder hose to bleeder screw, place in catch bottle, open bleeder screw, have assistant slowly depress brake pedal, close bleeder before pedal returns. Repeat until fluid flows clear without bubbles. Tighten each bleeder screw to specification. Refill reservoir frequently.
    ⚠Never allow brake fluid reservoir to run empty during bleeding or you will introduce air into the ABS pump itself.
    Torque spec

    Bleeder Screw16 Nm (12 lb-ft)
13. 13

    Perform ABS system bleeding with scan tool
    Reconnect negative battery cable. Using a scan tool with ABS bleeding capability, navigate to the ABS system bleeding function. Follow the scan tool prompts to cycle the ABS solenoid valves open and closed. This purges air trapped in the HCU. While the scan tool cycles the valves, have an assistant monitor brake pedal firmness and re-bleed individual wheels as needed. Repeat scan tool bleeding cycle 2-3 times or until pedal is firm.
    ℹ️Without scan tool cycling, air will remain trapped in the ABS hydraulic control unit and ABS will not function properly.
14. 14

    Verify brake pedal and check for leaks
    With engine running, pump brake pedal several times. Pedal should feel firm and not sink to floor. Inspect all brake line connections at the ABS pump for leaks. Wipe connections dry, then press brake pedal firmly and re-inspect. Check brake fluid reservoir level and top off to MAX line if needed.

Reassembly

1. Reinstall any air intake components or battery tray parts removed for access
2. Reinstall engine cover if equipped
3. Clean any brake fluid spills from painted surfaces and components with water
4. Dispose of old brake fluid according to local regulations

Verification

• Start engine and verify ABS warning light extinguishes after initial bulb check (within 3-5 seconds)
• Perform test drive in safe area and verify normal brake operation with firm pedal feel
• Perform ABS activation test at low speed (15-20 mph) on wet or loose surface to verify ABS pump cycles properly
• Use scan tool to check for ABS fault codes - there should be none stored
• Re-inspect all brake line connections for leaks after test drive
• Verify brake fluid reservoir is at proper level after test drive

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