GM Service Manual Online
For 1990-2009 cars only

Removal Procedure

Caution: To help avoid personal injury, due to a retained load on the brake modulator, the Gear Tension Relief function of the scan tool must be performed prior to removal of the ABS brake modulator assembly.


    Object Number: 221750  Size: SH
  1. Use the Scan Tool in order to perform the Gear Tension Relief Sequence.
  2. Disconnect the two brake solenoid valve electrical connectors (1).
  3. Disconnect the Brake Motor Pack electrical connector.
  4. Place a shop towel beneath the hydraulic modulator brake pipes (2) to prevent brake fluid from contaminating the motor pack or the electrical connectors.
  5. Disconnect the brake pipes (2) from hydraulic modulator (3). Note their positions.
  6. Plug the brake pipes to prevent loss or contamination of brake fluid.

  7. Object Number: 242622  Size: MH
  8. Remove the three nuts (5) and hydraulic modulator/motor pack assembly from the vehicle.

Installation Procedure


    Object Number: 242622  Size: MH
  1. Install the Hydraulic modulator assembly into the vehicle.
  2. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  3. Install Hydraulic modulator assembly to bracket mounting nuts (5).
  4. Tighten
    Tighten the Hydraulic modulator bracket mounting nuts to 5.4 N·m (48 lb in).


    Object Number: 221750  Size: SH
  5. Connect the brake pipes (2) to the hydraulic modulator (3).
  6. Tighten
    Tighten the tube nuts to 15 N·m (11 lb ft).

  7. Connect the Brake Motor Pack electrical connector.
  8. Connect the two brake solenoid valve electrical connectors (1).
  9. Bleed the system. Refer to Hydraulic Brake System Bleeding in Hydraulic Brakes.
  10. Perform the Diagnostic System Check - ABS