ABS Module

This procedure removes and replaces the ABS control module (HCU/EBCM assembly) on the 2008 Dodge Viper, including proper brake system bleeding and module recalibration.

Warnings

Tools required

Parts

• ABS control module (Hydraulic Control Unit with EBCM) × 1 — Use OEM specification - Mopar 68029177AB or equivalent
• Brake line sealing washers (if applicable to connections) × 4 — Use OEM specification
• DOT 4 brake fluid × 2 — 1 quart minimum

Fluids

• brake — 1.5 qt

Preparation

1. Verify you have a scan tool capable of Chrysler/Dodge ABS module programming and automated ABS bleeding procedures before beginning this job. Generic code readers will NOT suffice.
2. Park vehicle on level ground and ensure it cannot roll. Do NOT use parking brake during this procedure as brake system will be depressurized.
3. Place wheel chocks at all four wheels.
4. Open the hood and locate the brake fluid reservoir on the master cylinder. Use a turkey baster or fluid transfer pump to remove brake fluid from the reservoir until it is at the MIN line - this reduces spillage when lines are disconnected.
5. Disconnect the negative battery cable and wait 2 minutes before proceeding to allow airbag system capacitors to discharge.
6. Raise the vehicle on a lift or jack stands to allow access underneath for brake bleeding at all four wheels.
7. Remove the driver side front wheel to improve access to the inner fender area.

Procedure

1. 1

   Remove driver side front inner fender liner (partial)
   Working in the driver side front wheel well, locate the inner fender liner fasteners. Remove the forward section fasteners (typically 6-8 plastic push clips and Torx screws) securing the front portion of the liner to allow it to be folded back for access to the ABS module mounting area. You do not need to remove the entire liner - just enough to expose the inner fender where the ABS module mounts. Gently pull the liner away from the fender and secure it out of the way with tape or a bungee cord.
2. 2

   Locate and access the ABS control module
   The ABS module (Hydraulic Control Unit) is mounted to the driver side inner fender/shock tower area in the engine compartment. It is a rectangular aluminum block with multiple brake lines entering it and an electrical connector on top. Clean the area around the module and brake line fittings with brake cleaner to prevent contamination when lines are disconnected. Place absorbent pads or a drip pan below the module to catch brake fluid.
3. 3

   Disconnect the ABS module electrical connector
   Locate the large multi-pin electrical connector on the top or side of the ABS module. Press the locking tab or slide the release mechanism (typically a sliding lock) and carefully pull the connector straight off the module. Do not pull on the wires themselves. Move the connector aside and secure it so it does not hang on brake lines.
4. 4

   Mark and disconnect brake lines from ABS module
   There are typically 6 brake line connections on the ABS module (2 from master cylinder inlet, 4 outlet lines to wheels). Before disconnecting, use a paint marker or tape to label each line and its corresponding port on the module to ensure correct reinstallation. Using the appropriate flare nut wrench (typically 10mm), carefully loosen each brake line fitting. Expect significant brake fluid spillage - have rags ready. Once loosened, unthread fittings by hand and cap or plug the open lines immediately with rubber caps or by wrapping tightly with plastic wrap to minimize fluid loss and contamination. If fittings are corroded, apply penetrating oil and allow it to soak before attempting removal.
5. 5

   Remove ABS module mounting fasteners
   Locate the 3 bolts securing the ABS module bracket to the inner fender/body structure. These are typically 10mm hex head bolts. Remove all mounting bolts completely and retain them for reinstallation. Carefully lift the ABS module assembly away from the mounting surface - it will be heavy (approximately 8-10 lbs) and brake fluid will drip from the ports.
6. 6

   Prepare new ABS module for installation
   Remove the new ABS module from its packaging. Verify it matches the original unit in terms of connector configuration and brake line port locations. Remove any protective caps from the brake line ports. If new sealing washers are provided with the replacement module or brake line fittings, have them ready for installation. Do NOT remove caps until immediately before connecting lines.
7. 7

   Install new ABS module
   Position the new ABS module into the mounting location on the inner fender. Align the mounting holes and hand-start all 3 mounting bolts. Once all bolts are started, tighten them evenly in a star pattern to ensure the module seats properly against the mounting surface. Torque mounting bolts to the factory specification (verify against service info; if genuinely unavailable, approximately 17 ft-lbs is typical for M8 fasteners into body structure — do not exceed without confirming).
8. 8

   Reconnect brake lines to new ABS module
   Using your labels from disassembly, reconnect each brake line to its corresponding port on the new ABS module. If equipped with sealing washers, install new washers on each fitting before threading into the module. Hand-thread each fitting several turns to ensure proper engagement and prevent cross-threading. Once all fittings are hand-tight, use the flare nut wrench to snug each fitting firmly - verify factory torque specification for the brake line flare fittings (metric tube nuts, commonly in the 12-17 ft-lb range) before final tightening — do not rely on a generic value. Do not overtighten, as this can damage the flare seat or crack fittings.
9. 9

   Reconnect ABS module electrical connector
   Align the electrical connector with the module connector pins and press firmly until the connector seats completely. You should hear or feel a positive click when the locking mechanism engages. Verify the lock is fully engaged by gently pulling on the connector body - it should not pull off.
10. 10

    Refill brake fluid reservoir
    Return to the brake master cylinder and refill the reservoir to the MAX line with fresh DOT 4 brake fluid from a sealed container. Keep the reservoir topped off throughout the bleeding process - check it before bleeding each wheel.
11. 11

    Perform manual brake bleeding (base system)
    Bleed the brake system at all four wheels in the factory-specified sequence for this vehicle (verify against service information — commonly furthest-from-master-cylinder first, but confirm the exact order for the 2008 Viper before proceeding). At each wheel: attach a clear hose to the bleeder screw and submerge the other end in a container with clean brake fluid. Have an assistant pump the brake pedal 5-6 times and hold pressure. Open the bleeder screw 1/2 turn while assistant maintains pedal pressure - fluid and air will flow out. Close the bleeder before the pedal reaches the floor. Repeat until fluid flows with no air bubbles (typically 5-10 pumps per wheel). Check and top off the reservoir before moving to the next wheel. Tighten each bleeder screw to 7-9 ft-lbs when finished.
12. 12

    Perform ABS system automated bleed procedure
    Connect the OBD-II scan tool to the vehicle diagnostic port (located under the driver side dash). Turn the ignition to ON position (do not start engine). Navigate the scan tool menus to Chrysler/Dodge ABS system functions and select the automated bleeding or ABS motor cycle function. This will activate the ABS pump and cycle the internal valves to purge air trapped in the HCU. Follow the scan tool prompts - you may need to manually bleed at the wheels again during this process. Top off the reservoir as needed. Repeat the automated cycle 2-3 times or until the scan tool indicates successful completion.
13. 13

    Program new ABS module
    With a factory-capable scan tool (wiTECH/StarSCAN with subscription/online access) still connected and ignition ON, navigate to the ABS module programming or configuration menu. Note that many replacement HCU/EBCM units come pre-programmed and may only require configuration rather than a full flash. Follow the factory tool prompts to program/configure the module. Verify the exact procedure and whether the module requires flashing against factory service information for this vehicle. Do NOT turn off the ignition or disconnect the scan tool during programming. Once complete, the scan tool will confirm successful programming. Turn the ignition off, wait 10 seconds, then turn it back on to verify the ABS warning light illuminates briefly during bulb check and then extinguishes.
14. 14

    Verify brake pedal feel and ABS warning light
    With the engine off, pump the brake pedal firmly 15-20 times to deplete any stored vacuum reserve in the booster; the pedal should become firm/hard and hold steady without slowly sinking to the floor. The pedal should feel firm and not sink slowly to the floor. Start the engine - the pedal should drop slightly as vacuum assist activates, then remain firm. Verify the ABS warning light is OFF on the instrument cluster. If the light remains on, use the scan tool to read ABS fault codes and address any issues before proceeding.
15. 15

    Reinstall inner fender liner and wheel
    Reposition the driver side inner fender liner to its original location and reinstall all fasteners that were removed. Ensure the liner is properly seated and will not interfere with tire rotation. Reinstall the driver side front wheel and torque lug nuts to the factory specification (verify against service information for the 2008 Viper — commonly in the 110-130 ft-lb range, do not assume). Reconnect the negative battery cable.

Reassembly

1. All components should be reinstalled in reverse order of removal.
2. Ensure all brake line fittings are tightened securely but not over-torqued.
3. Verify the brake fluid reservoir is at the MAX line after all bleeding procedures are complete.
4. Double-check that the ABS module electrical connector is fully seated and locked.

Verification

• Start the engine and verify the ABS warning light extinguishes within 3-5 seconds.
• With the engine running, press the brake pedal firmly - it should feel solid with no sponginess and should not sink to the floor under steady pressure.
• Perform a low-speed test drive in a safe area: accelerate to 10-15 mph and apply brakes firmly to verify normal brake function.
• Perform an ABS activation test: on dry pavement in a safe area with no traffic, accelerate to 25-30 mph and apply brakes firmly enough to activate ABS (you should feel pulsation in the pedal and hear the ABS pump activate). Verify the vehicle stops in a controlled manner.
• After the test drive, check under the vehicle for any brake fluid leaks at the ABS module connections. Also check the fluid reservoir level - it should not have dropped significantly.
• Use the scan tool to verify no ABS fault codes are present after test drive.

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