This procedure covers the removal and replacement of the ABS module on a 2022 Rivian EDV 500, including brake system bleeding and recalibration.

Warnings

Tools required

Parts

• ABS module/HCU assembly × 1 — Use OEM Rivian part
• Brake line crush washers or seals × 6 — Use OEM specification
• ABS module mounting hardware kit × 1 — Use OEM specification if not included with module

Fluids

• DOT 4 Brake Fluid — 2 qt

Preparation

1. Park vehicle on level ground and engage parking brake
2. Place wheel chocks behind rear wheels
3. Disconnect 12V auxiliary battery (located in front cargo area) and wait 10 minutes for system capacitors to discharge
4. Verify high-voltage system is de-energized using appropriate isolation verification procedure per Rivian service manual
5. Remove engine cover/frunk liner to access front brake components and ABS module location
6. Raise vehicle and support on jack stands at all four corners
7. Remove all four wheels for access to brake lines
8. Photograph all brake line connections and routing for reference during reassembly
9. Have at least 2 quarts of fresh DOT 4 brake fluid available - do not use fluid from previously opened containers

Procedure

1. 1

   Locate and access ABS module
   The ABS module (Hydraulic Control Unit) is located in the front compartment on the driver side firewall area. Remove the protective cover by removing mounting fasteners. Disconnect the main electrical harness connector from the ABS module by pressing the locking tab and pulling straight out. Label the connector with tape for identification during reinstallation.
2. 2

   Depressurize brake system
   With the 12V battery disconnected, pump the brake pedal 20-30 times until it becomes firm and no additional movement occurs. This releases residual pressure in the ABS accumulator and hydraulic system. Verify pedal is firm before proceeding.
3. 3

   Disconnect brake lines from ABS module
   Using flare nut wrenches to prevent line damage, carefully loosen all six brake line connections on the ABS module (two lines per circuit: master cylinder inlet lines and four outlet lines to wheels). Work slowly to avoid stripping fittings. Position drain pan underneath to catch brake fluid. Once loose, unthread lines completely and immediately cap open ports with clean plastic plugs to prevent fluid loss and contamination entry.
4. 4

   Remove ABS module mounting fasteners
   Locate and remove all ABS module mounting bolts (typically 3-4 bolts securing module to mounting bracket). Support the module while removing final fastener as the assembly is heavy. Note the orientation and position of any ground straps or additional wiring that may be attached to mounting points.
5. 5

   Remove ABS module assembly
   Carefully lift the ABS module from its mounting location, being careful not to damage surrounding components or spill residual brake fluid. Place the old module in a safe location. Inspect the mounting bracket and area for any corrosion, damage, or leaked fluid that requires cleaning before installing the new unit.
6. 6

   Prepare new ABS module
   Remove the new ABS module from packaging and verify part number matches vehicle specifications. Inspect all brake line ports and electrical connectors for shipping caps and damage. Transfer any necessary brackets or hardware from old module to new module if not pre-installed. Ensure all port threads are clean and free of debris.
7. 7

   Install new ABS module
   Position the new ABS module into mounting location, aligning with mounting holes and ensuring proper orientation. Install mounting bolts and tighten in a cross-pattern to ensure even seating. Since specific torque values are not available, tighten mounting bolts firmly to secure the module without over-torquing aluminum threads (approximately 15-20 ft-lbs equivalent hand-tight plus 1/4 turn). Reconnect any ground straps.
8. 8

   Connect brake lines to new module
   Remove plugs from brake line ports on new module. Install new crush washers or sealing washers on each brake line fitting. Thread each brake line into correct port by hand first to ensure proper threading and prevent cross-threading. Use brake line routing photos taken during disassembly to ensure correct line placement. Once hand-tight, use flare nut wrench to tighten each connection firmly. Since specific torque values are not available, tighten to typical brake line specification of 11-13 ft-lbs or until snug plus 1/6 turn.
9. 9

   Reconnect electrical connector
   Remove any protective covers from electrical connector on new ABS module. Align electrical connector and press firmly until locking tab clicks into place. Gently tug on connector to verify it is fully seated and locked.
10. 10

    Bleed brake system
    Reconnect 12V auxiliary battery. Fill brake fluid reservoir with fresh DOT 4 brake fluid to MAX line. Using a brake pressure bleeder or assistant, bleed the brake system in this sequence: right rear, left rear, right front, left front. Open each bleeder valve 1/4 turn and allow fluid to flow until clean, bubble-free fluid emerges. Close bleeder valve before releasing brake pressure. Repeat sequence 2-3 times. Maintain reservoir level above MIN throughout bleeding process. The ABS module may require activation bleeding using scan tool - proceed to next step.
11. 11

    Perform ABS module activation bleeding
    Connect Rivian diagnostic scan tool to vehicle OBDII port. Navigate to ABS system functions and initiate 'ABS Automated Bleed' or 'HCU Activation' procedure. This cycles the ABS solenoids and pump to purge air from internal valves. Follow scan tool prompts, which will typically activate solenoids multiple times. During activation, monitor for proper pump operation and unusual noises. After activation sequence, repeat manual bleeding procedure at all four wheels as described in previous step.
12. 12

    Configure and calibrate new ABS module
    Using Rivian diagnostic scan tool, perform ABS module configuration/coding to match vehicle VIN and software version. This step is critical and requires factory-level access. Follow scan tool prompts to write vehicle configuration data to new module. Perform ABS system calibration including wheel speed sensor initialization, brake pressure sensor calibration, and regenerative braking integration parameters. Verify all calibration steps complete successfully with no error codes.
13. 13

    Clear diagnostic codes and verify operation
    Clear all diagnostic trouble codes from ABS system and other affected modules. Cycle ignition off and on. Verify ABS warning light follows proper startup sequence (illuminates briefly then extinguishes). Using scan tool, verify all ABS sensors show active readings and no current or pending fault codes are present. Check brake fluid level is at MAX mark in reservoir.

Reassembly

1. Reinstall all four wheels and torque lug nuts to Rivian specification (typically 150 ft-lbs for EDV 500 - verify in owner's manual)
2. Lower vehicle to ground
3. Reinstall engine cover/frunk liner and any trim pieces removed for access
4. Top off brake fluid reservoir to MAX line with fresh DOT 4 brake fluid
5. Double-check all brake line connections for tightness and any signs of leakage

Verification

• With vehicle safely supported, start vehicle and verify ABS warning light extinguishes within 3-5 seconds
• Using scan tool, perform active ABS system test and verify all solenoid valves and pump operate correctly
• Check all brake line connections for any seepage or leaks - there should be no fluid present
• Perform static brake pedal test: press brake pedal firmly and hold for 60 seconds - pedal should remain firm with no sinking
• Perform low-speed test in a safe area: drive vehicle at 5-10 mph and apply brakes firmly to verify proper brake function and pedal feel
• Perform controlled ABS activation test in a safe, empty area: at 20-25 mph on dry pavement, apply firm brake pressure to intentionally trigger ABS - verify proper pulsing feedback and straight-line stopping with no warning lights
• Test regenerative braking function at various speeds to ensure proper integration with mechanical brakes
• Drive vehicle and verify proper brake function under various conditions before returning to normal service
• If any abnormal behavior, warning lights, unusual noises, or pedal feel issues occur, DO NOT drive vehicle - tow to professional service facility immediately

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