Electronic Parking Brake Motor

Remove and replace the electronic parking brake motor on the rear brake caliper assembly of a 2024 Rivian EDV 500.

Warnings

Tools required

Parts

• Electronic parking brake motor/actuator × 1 — Use OEM specification
• EPB motor mounting bolts (if corroded) × 2 — Use OEM specification
• Brake fluid DOT 4 (for topping off only) × 1 — DOT 4 specification

Preparation

1. Park vehicle on level ground and engage parking brake initially
2. Place wheel chocks in front of front wheels
3. Connect diagnostic scan tool and verify communication with EPB control module
4. Put on high-voltage insulated gloves and verify high-voltage system is in safe/sleep mode
5. Disconnect 12V battery negative terminal and wait 5 minutes for system capacitor discharge
6. Connect 12V battery maintainer to prevent system reset during service
7. Raise rear of vehicle using floor jack at designated lift points per owner's manual
8. Secure vehicle on jack stands rated for electric vehicle weight (over 7,000 lbs)
9. Remove rear wheel on side requiring EPB motor replacement
10. Inspect brake caliper and rotor for damage or excessive wear that may have caused EPB failure

Procedure

1. 1

   Reconnect 12V battery temporarily for EPB retraction
   Reconnect the 12V battery negative terminal temporarily to power the diagnostic system. Keep high-voltage system in safe mode. Do not start or power on the vehicle fully.
2. 2

   Command EPB into service mode
   Using the diagnostic scan tool, navigate to the Electronic Parking Brake module. Select 'Service Mode' or 'Retract EPB Motor' function. This will fully retract the EPB actuator and caliper piston to provide clearance for motor removal. Wait for the system to confirm retraction is complete before proceeding.
   ⚠️Do not attempt to remove the EPB motor without first commanding it into service mode. The motor is under tension and may cause injury or damage.
3. 3

   Disconnect 12V battery again
   Once EPB retraction is confirmed complete, disconnect the 12V battery negative terminal again for electrical safety during motor removal. The EPB piston will remain retracted.
4. 4

   Disconnect EPB motor electrical connector
   Locate the EPB motor electrical connector on the rear of the brake caliper. Press the locking tab and carefully disconnect the connector. Inspect pins for corrosion or damage. Clean connector if necessary with electrical contact cleaner.
5. 5

   Remove EPB motor mounting bolts
   Locate the two EPB motor mounting bolts on the rear of the caliper assembly. These are typically T30 or T45 Torx bolts. Remove both bolts completely and retain for inspection. If bolts show corrosion or thread damage, replace with new OEM bolts.
6. 6

   Remove EPB motor from caliper
   Carefully pull the EPB motor assembly straight out from the caliper housing. The motor shaft engages with the caliper piston mechanism and may require slight rotation while pulling. Do not force or pry. If stuck, apply penetrating lubricant around the motor housing and wait 10 minutes.
7. 7

   Inspect caliper piston mechanism
   With the EPB motor removed, inspect the caliper piston mechanism for debris, corrosion, or damage. The piston should show the internal drive mechanism. Clean any debris with brake cleaner. If the piston mechanism shows damage or does not turn smoothly by hand, the caliper may require replacement.
8. 8

   Prepare new EPB motor
   Remove the new EPB motor from packaging and verify it matches the original part exactly. Check that the motor shaft rotates freely and is not mechanically locked. Apply a thin coat of anti-seize compound to the motor housing outer surface, avoiding the electrical connector area.
9. 9

   Install new EPB motor
   Align the new EPB motor shaft with the caliper piston drive mechanism. The motor may need to be rotated slightly to align the shaft splines with the piston mechanism. Push the motor firmly into the caliper housing until it seats completely flush. The motor should sit without gaps between the housing and caliper.
10. 10

    Install EPB motor mounting bolts
    Install the two EPB motor mounting bolts and hand-tighten initially. Tighten bolts in a cross pattern to manufacturer specification. Note: Torque specification not available in database - consult factory service manual or use 15-20 ft-lbs as typical for this application. Verify motor sits flush and secure after tightening.
11. 11

    Reconnect EPB motor electrical connector
    Reconnect the electrical connector to the EPB motor, ensuring it clicks fully into place. Gently tug on the connector to verify it is locked. Ensure the wire harness is routed away from the brake rotor and suspension components.
12. 12

    Reconnect 12V battery for calibration
    Reconnect the 12V battery negative terminal. The vehicle systems will initialize. Wait for all warning lights to cycle on the dashboard if visible.
13. 13

    Perform EPB calibration
    Using the diagnostic scan tool, navigate to the EPB module and select 'Calibration' or 'EPB Learn Procedure'. Follow the on-screen prompts to complete the calibration. This procedure teaches the EPB motor the full range of travel and sets proper parking brake engagement points. The calibration may take 2-5 minutes and will involve audible motor operation.
    ⚠Do not interrupt the calibration procedure once started. Loss of power during calibration may require repeat calibration or result in EPB fault codes.
14. 14

    Clear fault codes and verify operation
    Clear any stored EPB fault codes from the diagnostic system. Command the EPB to engage and disengage several times using the scan tool or parking brake switch to verify proper operation. Listen for smooth motor operation without grinding or clicking noises.
15. 15

    Reinstall wheel and perform final checks
    Reinstall the rear wheel and torque lug nuts to specification in a star pattern. Note: Torque specification not available in database - typically 120-150 ft-lbs for this vehicle class. Lower vehicle from jack stands. Perform final EPB engagement test with vehicle weight on wheels. Check brake fluid level in reservoir and top off with DOT 4 if needed.

Reassembly

1. Torque wheel lug nuts to proper specification in a star pattern
2. Verify no tools or parts are left in wheel well area
3. Remove jack stands and lower vehicle completely
4. Remove wheel chocks
5. Verify brake fluid level is between MIN and MAX marks

Verification

• With vehicle on level ground, engage parking brake using switch and verify indicator light illuminates on dashboard
• Attempt to push vehicle by hand with parking brake engaged - vehicle should not roll
• Disengage parking brake and verify indicator light turns off
• Test drive vehicle in safe area at low speed and verify normal brake operation
• Park on slight incline and verify parking brake holds vehicle without rolling
• Use diagnostic tool to verify no EPB fault codes are present
• Verify EPB motor operates smoothly without unusual noises during engagement and disengagement
• Check that brake warning lights do not remain illuminated on dashboard

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