Electronic Parking Brake Motor

This procedure covers the removal and replacement of the electronic parking brake motor on a 2023 Rivian EDV 500, requiring rear wheel removal and brake system diagnostics.

Warnings

Tools required

Parts

• Electronic parking brake motor assembly × 1 — Use OEM Rivian specification
• EPB motor mounting bolts × 1 — Use OEM specification
• EPB electrical connector seal × 1 — Use OEM specification if damaged

Fluids

• DOT 4 Brake Fluid — 0.5 qt

Preparation

1. Park vehicle on level surface and verify transmission is in Park
2. Chock front wheels securely with wheel chocks rated for commercial vehicle weight
3. Connect Rivian diagnostic scan tool and verify communication with vehicle systems
4. Open the front hood and locate the 12V service battery in the front compartment
5. Disconnect the 12V service battery negative terminal and wait 5 minutes for system capacitor discharge
6. Verify high-voltage system status is 'Safe' on diagnostic tool display before proceeding
7. Raise vehicle on lift or with heavy-duty floor jack, supporting at approved lift points per service manual
8. Install jack stands rated for minimum 8,000 lbs at manufacturer-specified support points
9. Remove the rear wheel on the side requiring EPB motor replacement using appropriate socket
10. Inspect brake rotor, caliper, and surrounding area for fluid leaks or damage

Procedure

1. 1

   Enter EPB service mode
   Using the Rivian diagnostic scan tool, navigate to Brake System > Electronic Parking Brake > Service Functions. Select 'EPB Service Mode' and follow prompts to retract the parking brake caliper pistons fully. The system will display 'Service Mode Active' when ready. The EPB motor will retract to its full open position. Do not proceed until confirmation is displayed.
2. 2

   Disconnect EPB motor electrical connector
   Locate the EPB motor on the rear of the brake caliper assembly. The motor is a cylindrical unit with an electrical connector on the end cap. Press the locking tab on the electrical connector and carefully pull straight back to disconnect. Inspect the connector pins for corrosion or damage. If connector seal is damaged, mark for replacement.
3. 3

   Remove EPB motor mounting bolts
   Identify the two Torx mounting bolts securing the EPB motor to the caliper housing. Apply penetrating oil if there is visible corrosion. Using the appropriate Torx driver (typically T30 or T40), remove both mounting bolts while supporting the motor assembly with your other hand. Note the bolt length and location for reinstallation.
4. 4

   Extract EPB motor from caliper
   Carefully pull the EPB motor straight out from the caliper housing. The motor shaft engages with the caliper piston mechanism and may require gentle rotation while pulling. Do not use excessive force. If motor is seized, verify service mode is active and apply additional penetrating oil around the motor housing seam. Allow 10 minutes for penetration before attempting removal again.
5. 5

   Inspect caliper piston mechanism
   With the EPB motor removed, inspect the exposed caliper piston mechanism and threaded spindle. Check for corrosion, debris, or damage to the threads. The piston should be fully retracted in service mode. Clean the spindle threads with a wire brush and apply a thin coating of high-temperature brake grease to the threads. Do not allow grease to contact brake pads or rotor.
6. 6

   Test new EPB motor operation
   Before installation, connect the new EPB motor to the vehicle electrical connector (do not install in caliper yet). Using the diagnostic scan tool, command a brief EPB motor test. Verify the motor shaft rotates smoothly in both directions and stops when commanded. Listen for unusual grinding or binding noises. If motor does not operate correctly, verify correct part number and connector integrity.
7. 7

   Install new EPB motor
   Disconnect the electrical connector from the test-fitted motor. Align the new EPB motor shaft with the caliper piston spindle mechanism. The motor will only fit in one orientation. Gently push the motor into the caliper housing while slowly rotating clockwise approximately 1/8 turn to engage the splines. The motor should seat flush against the caliper housing mounting surface.
8. 8

   Install EPB motor mounting bolts
   Install the two Torx mounting bolts through the EPB motor mounting flange into the caliper housing. Start both bolts by hand to ensure proper thread engagement. Tighten bolts in a cross-pattern to ensure even seating. Since no torque specification is provided in the database, tighten to manufacturer specification from service documentation. If unavailable, tighten to snug specification and mark for professional torque verification.
9. 9

   Reconnect EPB motor electrical connector
   Align the electrical connector with the EPB motor pins, ensuring proper orientation. Push connector firmly until the locking tab clicks into place. Gently tug on the connector to verify it is fully seated and locked. If new connector seal was required, ensure it is properly installed before connection.
10. 10

    Exit EPB service mode and calibrate system
    Using the diagnostic scan tool, navigate to EPB Service Functions and select 'Exit Service Mode'. The system will command the EPB motor to perform an automatic calibration cycle. The motor will extend and retract multiple times while learning the caliper piston position. This process takes 30-60 seconds. Do not interrupt power during calibration. When complete, the scan tool will display 'Calibration Complete' or 'EPB System Ready'.
11. 11

    Verify EPB system operation
    Using the diagnostic scan tool, command the EPB to engage and release three times while observing motor operation. Listen for smooth motor operation without grinding or hesitation. Check for diagnostic trouble codes related to the EPB system. Clear any codes and verify they do not return. If codes persist, verify connector integrity and motor installation.
12. 12

    Check brake fluid level
    Access the brake fluid reservoir under the front hood. Check the fluid level and top off with DOT 4 brake fluid if needed to bring level to the MAX mark. Piston retraction during service mode may have slightly lowered fluid level. Ensure reservoir cap is properly sealed after topping off.

Reassembly

1. Reinstall the rear wheel and hand-tighten lug nuts in a star pattern
2. Carefully lower vehicle from jack stands and remove from lift
3. Torque wheel lug nuts to manufacturer specification in star pattern using torque wrench
4. Reconnect the 12V service battery negative terminal
5. Verify all tools and parts have been removed from vehicle
6. Do not drive vehicle until verification procedures are completed successfully

Verification

• With vehicle still in Park and chocks in place, start the vehicle and verify no brake system warning lights are illuminated on the instrument cluster
• Using the diagnostic scan tool, perform a complete EPB system test and verify no diagnostic trouble codes are present
• Press the EPB switch to engage parking brake and verify the motor operates smoothly and the parking brake indicator illuminates on the dash
• Release the EPB using the switch and verify the indicator extinguishes and the motor retracts fully
• Perform three complete engage/release cycles and confirm consistent operation each time
• Pump the brake pedal several times to ensure proper pedal feel and height
• With vehicle on level ground and transmission in Neutral, verify the parking brake holds the vehicle securely when engaged
• Perform a slow-speed test drive in a safe area, testing both service brakes and parking brake hold function
• After test drive, recheck for diagnostic codes and verify EPB operates normally
• If any abnormalities are detected during verification, do not return vehicle to service and consult a professional technician immediately

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

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