This procedure covers the removal and replacement of the ABS hydraulic control unit (HCU/pump) on a 2022 Rivian EDV 500 electric delivery van with dual motor AWD configuration.

Warnings

Tools required

Parts

• ABS Hydraulic Control Unit (Pump Assembly) × 1 — Use OEM specification
• Brake line sealing washers/gaskets × 1 — Use OEM specification
• Wiring harness connector seals (if damaged) × 1 — Use OEM specification

Fluids

• DOT 4 Brake Fluid — 2 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Ensure 12V battery is fully charged (critical for scan tool and module programming)
3. Follow Rivian high voltage safety lockout procedure: disable HV system via vehicle settings, remove service disconnect plug from HV battery, verify zero voltage with meter, install lockout tag
4. Wait minimum 5 minutes after HV disconnect for capacitor discharge
5. Disconnect 12V negative battery cable
6. Remove front cargo area floor panels or access panels to reach ABS pump location (typically mounted in front underfloor area)
7. Have adequate lighting and access to work area
8. Prepare clean workspace for removed components

Procedure

1. 1

   Access ABS pump assembly
   Remove underbody panels or cargo area access covers as needed to expose the ABS hydraulic control unit. The unit is typically located in the front section of the cargo area or under the floor near the driver's side. Remove any wire harness clips or brackets securing the wiring to surrounding structure.
2. 2

   Depressurize brake system
   With ignition OFF and HV system disabled, press brake pedal firmly 20-30 times to depressurize the brake accumulator and hydraulic system. Continue until pedal becomes noticeably firmer and no further change occurs.
3. 3

   Document brake line positions
   Photograph or clearly label all brake lines connected to the ABS pump. There will typically be 4-6 brake lines corresponding to each wheel circuit plus master cylinder connections. Note the routing and orientation of each line for proper reassembly.
4. 4

   Disconnect electrical connectors
   Release the locking tabs and disconnect all electrical connectors from the ABS pump assembly. The main connector is typically a large multi-pin connector with a secondary locking mechanism. Note the connector orientation and any alignment features. Secure connectors away from work area.
5. 5

   Disconnect brake lines
   Using appropriate brake line wrenches to prevent rounding, loosen and remove each brake line fitting from the ABS pump. Work from the top down if possible. Have drain pan positioned to catch brake fluid. Cap or plug each brake line immediately after removal to prevent fluid loss and contamination. Remove and discard all sealing washers.
6. 6

   Remove ABS pump mounting fasteners
   Remove the mounting bolts or nuts securing the ABS hydraulic control unit to its bracket. Typically there are 2-4 fasteners. Support the unit while removing the final fastener as the assembly is heavy (approximately 10-15 lbs).
7. 7

   Remove ABS pump assembly
   Carefully lift and remove the ABS pump assembly from the vehicle. Keep the unit upright if possible to minimize brake fluid spillage. Place on clean work surface. Inspect the mounting location for any leaked brake fluid or corrosion and clean as necessary.
8. 8

   Prepare new ABS pump
   Unpack new ABS pump assembly and verify it matches the original unit. Install new sealing washers on all brake line ports. Some units come pre-filled with brake fluid; verify fluid level if there is a visible reservoir. Ensure all protective caps and plugs are removed before installation.
9. 9

   Install new ABS pump
   Position the new ABS hydraulic control unit into the mounting location, aligning mounting holes and ensuring no wires or lines are pinched. Install mounting fasteners and tighten in a cross pattern to secure unit evenly to bracket. Verify unit is firmly mounted with no movement.
10. 10

    Connect brake lines
    Install brake lines to the ABS pump in the correct positions per earlier documentation. Use new sealing washers on each fitting. Thread fittings by hand first to avoid cross-threading, then tighten with brake line wrenches. Ensure each line is properly seated and torqued to prevent leaks. Double-check that each line goes to the correct port.
11. 11

    Reconnect electrical connections
    Connect all electrical connectors to the ABS pump, ensuring positive engagement of locking tabs and secondary locks. Verify connectors are fully seated and secure. Route wiring away from hot or moving components and secure with clips or ties.
12. 12

    Bleed brake system
    Fill brake fluid reservoir with fresh DOT 4 brake fluid. Bleed the brake system starting with the wheel furthest from the ABS pump (typically right rear) and working toward the closest (typically left front). Use a pressure bleeder or two-person manual bleeding method. For ABS systems, a scan tool may be required to cycle the ABS pump and valves during bleeding to purge all air. Continue bleeding until fluid flows clear with no bubbles from each wheel.
13. 13

    Perform ABS configuration
    Using a factory-level scan tool with Rivian access, perform ABS module configuration or coding procedure. This typically includes component initialization, system test, and potentially VIN programming. Follow all scan tool prompts. Clear any diagnostic trouble codes that were set during the replacement procedure.
14. 14

    Reconnect vehicle power systems
    Reconnect 12V negative battery cable. Follow Rivian procedure to re-enable high voltage system: remove lockout tag, reinstall HV service disconnect plug, verify proper seating, enable HV system through vehicle interface. Verify vehicle powers up normally and no warning lights remain illuminated beyond initial bulb check.

Reassembly

1. Reinstall all underbody panels and cargo area access covers removed during disassembly
2. Verify all fasteners are tightened and no tools or parts are left in vehicle
3. Top off brake fluid reservoir to proper level with fresh DOT 4 fluid
4. Clean any spilled brake fluid from vehicle surfaces immediately

Verification

• With vehicle in PARK and parking brake engaged, start vehicle and verify ABS warning light extinguishes after bulb check
• Press brake pedal firmly and verify proper firmness with no excessive travel or spongy feel
• Using scan tool, verify ABS module communication and no active fault codes
• Perform scan tool ABS self-test function if available and verify all components pass
• Check all brake line connections at ABS pump for leaks while assistant applies firm brake pedal pressure
• Perform low-speed test drive in safe area and verify normal brake operation
• Perform controlled ABS activation test (if safe area available) by braking firmly on loose surface at 15-20 mph to verify ABS pump cycles properly
• Recheck brake fluid level after test drive and top off if needed
• Verify no warning lights on instrument cluster and all brake functions operate normally

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