ABS Pump

Remove and replace the ABS hydraulic control unit (HCU) assembly, including disconnecting brake lines, electrical connections, and bleeding the brake system after installation.

Warnings

Tools required

Parts

• ABS hydraulic control unit (HCU) × 1 — Use OEM specification
• Brake fluid DOT 4 × 2 — Mopar or equivalent

Fluids

• brake — 1 qt

Preparation

1. Park vehicle on level ground and apply parking brake
2. Place wheel chocks behind rear wheels
3. Open hood and secure in upright position
4. Disconnect negative battery cable and wait 2 minutes for airbag system to discharge
5. Raise front of vehicle and support securely on jack stands at manufacturer-specified lift points
6. Remove both front wheels
7. Place drain pan under work area to catch brake fluid spillage

Procedure

1. 1

   Locate ABS hydraulic control unit
   The ABS HCU is mounted in the engine compartment. Consult the factory service manual for the exact HCU location on this vehicle before proceeding. It consists of the hydraulic control unit with integrated electric pump motor and electronic control module mounted on top. Inspect the unit to familiarize yourself with brake line routing and electrical connector locations.
2. 2

   Disconnect ABS electrical connector
   Locate the main ABS control module connector on top of the HCU assembly. Press the connector release tab and carefully pull the connector straight up and away from the module. Position the harness out of the way and secure it to prevent contamination from brake fluid.
3. 3

   Disconnect pump motor electrical connector
   Locate the ABS pump motor electrical connector on the side of the hydraulic unit. Depress the connector lock tab and disconnect the pump motor harness. Move the harness away from the work area.
4. 4

   Label and disconnect brake lines from HCU
   Multiple brake lines connect to the ABS HCU (typically inlet lines from the master cylinder and outlet lines to the wheel brakes). Verify the exact number and routing of brake lines against the factory service manual before disconnecting. Use a marker or tape to label each brake line connection for correct reinstallation. Using flare nut wrenches to prevent rounding, loosen each brake line fitting approximately 1-2 turns. Have drain pan positioned below. Once all fittings are loosened, completely remove each brake line and immediately cap or plug the open ends to prevent fluid loss and contamination. Expect significant brake fluid drainage. Note: Use only flare nut wrenches on brake line fittings. Standard open-end wrenches will round the soft steel tube-nut fittings.
   ⚠Use only flare nut wrenches on brake line fittings. Standard open-end wrenches will round the soft brass fittings.
5. 5

   Remove HCU mounting hardware
   The ABS HCU is secured to its mounting bracket with mounting bolts/nuts. Remove the fasteners securing the HCU assembly, referring to the factory service manual for the exact number and torque specification. The unit is heavy due to the pump motor and residual brake fluid, so support it during removal.
6. 6

   Remove ABS hydraulic control unit
   Carefully lower the ABS HCU assembly away from the mounting bracket. Keep the unit upright to minimize fluid spillage. Place the old unit in the drain pan or suitable container to catch any remaining brake fluid draining from the ports.
7. 7

   Prepare new ABS hydraulic control unit
   Remove the new ABS HCU from its packaging. Verify the part number matches the original unit by cross-referencing the factory parts catalog for this specific vehicle before installation. Inspect all brake line ports and electrical connectors for shipping plugs or protective covers and remove them. Check that the mounting bracket interface is clean and free of damage.
8. 8

   Install new ABS hydraulic control unit
   Position the new ABS HCU onto the frame rail mounting bracket, aligning the mounting holes. Install the mounting bolts and torque to specification. Ensure the unit is securely mounted and properly oriented with brake line ports accessible.
9. 9

   Connect brake lines to new HCU
   Remove the caps or plugs from the brake line ends and HCU ports. Thread each brake line fitting into the correct port on the new HCU using the labels applied during removal. The two larger inlet lines connect to the upper ports from the master cylinder; the four outlet lines connect to the lower ports leading to each wheel. Hand-tighten all fittings first to ensure proper threading, then tighten securely with flare nut wrenches. Do not overtighten as this can strip or damage the steel tube-nut fittings.
10. 10

    Reconnect electrical connectors
    Connect the ABS pump motor electrical connector to the pump assembly until it clicks into place. Connect the main ABS control module connector to the module on top of the HCU, ensuring it seats fully and locks securely.
11. 11

    Reinstall front wheels
    Install both front wheels and hand-tighten lug nuts in a star pattern. Lower the vehicle until wheels just contact the ground but suspension is not fully loaded. Torque lug nuts to specification in a star pattern. Fully lower vehicle and remove jack stands.
12. 12

    Reconnect battery and fill brake fluid reservoir
    Reconnect the negative battery cable. Open the brake fluid reservoir cap under the hood. Fill the reservoir to the MAX line with fresh brake fluid of the specification marked on the reservoir cap (verify DOT 3 or DOT 4 for this vehicle). Do not reuse old brake fluid.
13. 13

    Perform initial manual brake bleeding
    Bleed the brake system using the manual bleeding procedure in the factory-specified sequence. Consult the factory service manual for the correct bleed order for this vehicle (commonly starting at the wheel furthest from the master cylinder). At each wheel, attach a clear hose to the bleeder screw and submerge the other end in a container of clean brake fluid. Have an assistant pump the brake pedal 3-4 times and hold, then open the bleeder screw. Close bleeder before pedal reaches the floor. Repeat until fluid flows clear without air bubbles. Torque bleeder screws to specification after bleeding each wheel. Monitor and refill the brake fluid reservoir frequently during this process.
    ⚠Never allow the brake fluid reservoir to run dry during bleeding or air will enter the ABS hydraulic unit requiring complete re-bleeding.
14. 14

    Perform ABS system bleeding with scan tool
    Connect a Chrysler-capable scan tool (DRB III or equivalent with ABS bleed function) to the vehicle's diagnostic connector. Navigate to the ABS bleeding function. Follow the scan tool prompts to activate the ABS pump and cycle the solenoid valves. This purges air from the internal ABS valves and chambers that cannot be reached through manual bleeding. During the automated bleeding cycle, monitor the brake fluid reservoir and maintain level. The scan tool will cycle each valve multiple times. After completing the automated sequence, perform one additional round of manual bleeding at all four wheels using the same sequence as before (RR, LR, RF, LF).
15. 15

    Final brake fluid level and system check
    Top off the brake fluid reservoir to the MAX line with fresh DOT 4 brake fluid. Secure the reservoir cap. With the engine off, pump the brake pedal firmly 15-20 times. The pedal should become firm and hold steady pressure. Inspect all brake line connections at the ABS HCU for leaks. Start the engine and verify the ABS warning light illuminates briefly during startup then extinguishes. If the ABS light remains on, use the scan tool to retrieve diagnostic trouble codes and address any issues before operating the vehicle.

Reassembly

1. Reinstallation follows removal in reverse order
2. Ensure all brake line connections are tight and leak-free before operating vehicle
3. Always torque wheel lug nuts in a star pattern to specification
4. Verify brake pedal firmness and ABS warning light operation before test drive

Verification

• With engine running, brake pedal should be firm with normal travel and no sponginess
• ABS warning light should extinguish within 3-5 seconds of starting engine
• No brake fluid leaks visible at any ABS HCU connection points
• Test drive in a safe area at low speed and verify normal brake operation
• Perform a controlled ABS activation test on dry pavement by firmly applying brakes from 20-25 mph - you should feel pulsing through the pedal and hear the ABS pump activate
• After test drive, recheck all brake line fittings for leaks and brake fluid reservoir level

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