ABS Module

Remove and replace the ABS control module (Hydraulic Control Unit/HCU) on a 2005 Dodge Viper, including brake line disconnection, fluid recovery, installation, bleeding, and system verification.

Warnings

Tools required

Parts

• ABS Control Module (HCU) × 1 — Use OEM specification - Mopar part number varies by production date
• Brake line crush washers (if equipped) × 6 — Use OEM specification

Fluids

• DOT 4 brake fluid — 1 qt

Preparation

1. Park vehicle on level, solid ground. Apply parking brake and place wheel chocks behind rear wheels.
2. Open brake fluid reservoir and verify fluid level. Mark current level for reference.
3. Disconnect negative battery terminal and wait 2 minutes to allow airbag system capacitors to discharge.
4. Raise front of vehicle with floor jack and support on jack stands at manufacturer-specified lift points on frame rails.
5. Remove both front wheels and store in safe location.
6. Place absorbent rags and catch containers under brake line routing near ABS module location.
7. Locate ABS module (mounted on driver side frame rail forward of driver's footwell, accessible from underneath vehicle).
8. Have fresh DOT 4 brake fluid, catch containers, and all tools staged before beginning brake line disconnection.

Procedure

1. 1

   Disconnect ABS module electrical connector
   Locate the large multi-pin electrical connector on top of the ABS module. Press the locking tab and carefully pull the connector straight away from the module. Do not allow brake fluid to contact the connector pins. Secure the connector away from the work area using a wire tie or by draping it over a nearby component.
   ⚠Inspect connector pins for corrosion or damage before disconnection. Damaged pins may indicate internal module failure.
2. 2

   Disconnect brake lines from ABS module inlet ports
   Identify the brake line inlet ports on the ABS module where lines from the master cylinder connect. Verify the exact port count and routing against the vehicle service manual before disconnection. Using a flare nut wrench of appropriate size, loosen each brake line fitting 1-2 turns while supporting the module body to prevent rotation. Brake fluid will begin draining immediately into your catch container. Once fittings are loose, completely unthread each line and immediately cap the open ends with rubber plugs or plastic caps to prevent fluid loss and contamination. Note the position of each line for reinstallation.
   ⚠Use only flare nut wrenches to prevent rounding of brake line fittings. Standard open-end wrenches will damage the soft brass/steel fittings.
   Torque spec

   Brake Line Fittings15 Nm (11 lb-ft)
3. 3

   Disconnect brake lines from ABS module outlet ports
   Identify the brake line outlet ports routing to the wheel circuits. Verify the exact port count against the vehicle service manual before disconnection. Using the flare nut wrench, loosen and remove each outlet line using the same technique as the inlet lines. Cap all open ports on the module and all disconnected brake line ends immediately. Allow all residual fluid to drain into catch containers. Wipe any spilled fluid from the module mounting area and surrounding components with brake cleaner and clean rags.
   Torque spec

   Brake Line Fittings15 Nm (11 lb-ft)
4. 4

   Remove ABS module mounting fasteners
   Locate the mounting bolts securing the ABS module to the frame rail bracket. Verify the exact bolt count and head size against the vehicle service manual. Using a socket and ratchet, remove all 3 bolts and retain them for reinstallation. Support the module with one hand while removing the final bolt, as the unit weighs approximately 8-10 pounds and may drop when freed.
   Torque spec

   ABS Module Bolts10 Nm (7 lb-ft)
5. 5

   Remove ABS module from vehicle
   Carefully lower the ABS module assembly away from the mounting bracket, maneuvering it past any brake lines, wiring harnesses, or frame obstructions. The unit may have residual brake fluid inside; keep it upright and drain any remaining fluid into your catch container. Inspect the mounting bracket for corrosion or damage. Clean the mounting surface with brake cleaner if necessary.
   ℹ️If the old module is being returned as a core, keep it upright in a sealed plastic bag to prevent fluid leakage during transport.
6. 6

   Prepare new ABS module for installation
   Remove the new ABS module from its packaging. Verify that all inlet and outlet ports have protective caps installed. Inspect the electrical connector for any shipping damage or corrosion. Check that the mounting bolt holes align with the bracket by test-fitting the module (without connecting lines). If the new module came with replacement crush washers or sealing washers for brake line fittings, have them ready for installation.
   ⚠Do not remove protective caps from brake ports until immediately before connecting brake lines. This prevents contamination of the internal hydraulic passages.
7. 7

   Install new ABS module to mounting bracket
   Position the new ABS module onto the frame rail mounting bracket, aligning all 3 mounting bolt holes. Hand-thread all 3 mounting bolts to ensure proper alignment before tightening. Once all bolts are started, torque them in a crossing pattern (alternating between opposite sides) to the specified torque value. This ensures even clamping force and prevents distortion of the module housing.
   Torque spec

   ABS Module Bolts10 Nm (7 lb-ft)
8. 8

   Connect brake lines to ABS module outlet ports
   Remove caps from the 4 outlet ports and the corresponding brake line ends (lines routing to each wheel). Thread each brake line fitting by hand into its corresponding outlet port, ensuring proper alignment and that threads engage smoothly without cross-threading. Refer to notes made during removal to ensure correct line routing. Once all outlet fittings are hand-tight, use the flare nut wrench to snug each fitting, then torque to specification in a sequential pattern. If crush washers were provided, install them before threading fittings.
   ⚠Cross-threading brake line fittings will require line replacement. Always hand-thread fittings at least 3-4 turns before using a wrench.
   Torque spec

   Brake Line Fittings15 Nm (11 lb-ft)
9. 9

   Connect brake lines to ABS module inlet ports
   Remove caps from the 4 inlet ports and corresponding brake line ends (lines from master cylinder and modulator). Thread each inlet line fitting by hand, then torque to specification using the flare nut wrench. Double-check that all brake line connections are properly seated and torqued. Visually inspect each connection for proper alignment and absence of cross-threading.
   Torque spec

   Brake Line Fittings15 Nm (11 lb-ft)
10. 10

    Reconnect ABS module electrical connector
    Align the electrical connector with the receptacle on top of the ABS module. Press firmly until the locking tab clicks into place. Gently tug on the connector body to verify it is fully seated and locked. Wipe any brake fluid from the area around the connector.
    ⚠Ensure connector pins are completely dry before connection. Brake fluid contamination will damage the control module electronics.
11. 11

    Refill brake fluid reservoir
    Working from the engine bay, fill the brake fluid reservoir to the MAX line using fresh DOT 4 brake fluid from a sealed container. Do not reuse old brake fluid collected during removal. Keep the reservoir filled above the MIN line throughout the bleeding process to prevent air from entering the master cylinder.
    ⚠Never let the brake fluid reservoir run dry during bleeding. Air entering the master cylinder will require complete system re-bleeding and may require bench bleeding the master cylinder.
12. 12

    Bleed brake system using manual method
    Attach a clear hose to the bleeder screw and submerge the other end in a container of fresh brake fluid. Have an assistant pump the brake pedal 3-4 times and hold pressure. Open the bleeder screw 1/2 turn while the assistant maintains pedal pressure. Close the bleeder before the pedal reaches the floor. Repeat until fluid flows without air bubbles. Torque bleeder screw to specification. Follow the manufacturer-specified bleed sequence for this vehicle, verifying wheel order against the service manual. Check and refill the reservoir frequently during bleeding. fluid flows without air bubbles. Torque bleeder screw to specification. Repeat this process for left rear, right front, then left front. Check and refill the reservoir frequently during bleeding.
    ⚠️The brake pedal must NEVER be released while the bleeder screw is open. This will draw air into the system through the bleeder threads.
    Torque spec

    Bleeder Screw14 Nm (10 lb-ft)
13. 13

    Perform ABS module internal bleeding (if scan tool available)
    If you have access to a scan tool with ABS bleeding capability (Chrysler DRB-III, StarSCAN, or equivalent aftermarket tool), connect the scan tool to the OBD-II port and navigate to the ABS system bleeding function. Follow the scan tool prompts to cycle the ABS pump and solenoid valves, which will purge trapped air from the internal hydraulic passages. During this process, the scan tool will instruct you to bleed specific wheels in sequence. Monitor the brake fluid reservoir and refill as needed. This step is strongly recommended after ABS module replacement.
    ℹ️Without a scan tool, air may remain trapped in the ABS module internal passages. While basic braking function will return, ABS performance may be degraded until the system self-bleeds during normal driving and ABS activation events.
14. 14

    Verify brake pedal feel and reinstall wheels
    With the engine off, pump the brake pedal 15-20 times. The pedal should become firm and maintain pressure without sinking. If the pedal remains soft or spongy, repeat the bleeding process. Once a firm pedal is achieved, fill the brake fluid reservoir to the MAX line. Reinstall both front wheels, hand-threading all lug nuts before lowering the vehicle. Lower the vehicle from jack stands, then torque lug nuts in a star pattern to specification.
    ⚠️Do NOT drive the vehicle if the brake pedal is soft, spongy, or travels more than halfway to the floor. These symptoms indicate air in the system or incorrect installation. Re-bleed the system completely.
    Torque spec

    Wheel Lug Nuts136 Nm (100 lb-ft)
15. 15

    Reconnect battery and clear ABS fault codes
    Reconnect the negative battery terminal and torque to specification if applicable. Turn the ignition to the ON position without starting the engine. The ABS warning light should illuminate briefly and then extinguish after 3-5 seconds. If the light remains on, use a scan tool to read and clear any stored ABS fault codes. Start the engine and verify the ABS light remains off. If the light stays illuminated, diagnose the fault codes before proceeding to test drive.
    ℹ️Some fault codes may require a short test drive (below 15 mph in a safe area) before they will clear automatically.

Reassembly

1. Installation is the reverse of removal with the following critical points: All brake line fittings must be torqued to specification using a flare nut wrench. The ABS module mounting bolts must be torqued in a crossing pattern. The brake fluid reservoir must be monitored and refilled throughout the bleeding process. Wheel lug nuts must be torqued in a star pattern after lowering the vehicle.

Verification

• With the engine running, verify the ABS warning light is off and no warning messages appear in the instrument cluster.
• Perform a stationary brake pedal test: pump the pedal with the engine running and verify a firm, high pedal with no sponginess or excessive travel.
• In a safe, empty area (parking lot), perform a low-speed test drive (10-15 mph) and verify normal brake operation without pulling to either side.
• Perform a controlled ABS activation test on a safe surface: at 20-25 mph on dry pavement, apply firm brake pressure to activate ABS. Verify normal pulsing feedback through the pedal and steering wheel, indicating proper ABS function.
• After test drive, park the vehicle and inspect all brake line connections at the ABS module for signs of leakage. Check brake fluid level and top off if needed.
• Road test the vehicle under normal driving conditions, verifying proper brake response and ABS function. The ABS warning light should remain off during all driving conditions.

More procedures for this vehicle