GM Service Manual Online
For 1990-2009 cars only

Object Number: 900989  Size: SH

Caution: Refer to Brake Fluid Irritant Caution in the Preface section.

Notice: Refer to Brake Fluid Effects on Paint and Electrical Components Notice in the Preface section.

Notice: Always connect or disconnect the wiring harness connector from the EBCM/EBTCM with the ignition switch in the OFF position. Failure to observe this precaution could result in damage to the EBCM/EBTCM.

Notice: There is a first design and second design of brake pipe flare for the hydraulic brake pipes and system components used on this vehicle. Do NOT mis-match flare types. If the flare types are mis-matched, damage to the pipes and/or components, and/or a brake fluid leak may occur.

   • First design, ISO flare (1)
   • Second design, double inverted flare (2)

Removal Procedure


    Object Number: 927845  Size: SH
  1. Turn the ignition switch to the OFF position.
  2. Remove the transmission control module (TCM), if equipped, from the mounting bracket and position aside.

  3. Object Number: 927847  Size: SH
  4. Clean the brake modulator assembly pipe fitting areas of any accumulated dirt and foreign material.
  5. Disconnect the electrical connector from the electronic brake control module (EBCM).

  6. Object Number: 927833  Size: SH
  7. Place a shop towel under the brake modulator assembly to catch any brake fluid loss.
  8. Important: Prior to disconnecting the brake pipes from the antilock brake system (ABS) modulator assembly, note the locations of the brake pipes to the valve assembly, to aid during installation.

  9. Disconnect the caliper and wheel cylinder brake pipes from the brake pressure modulator valve (BPMV).
  10. Cap the brake pipe ends to prevent brake fluid loss and contamination.
  11. Disconnect the master cylinder brake pipes from the BPMV.
  12. Cap the brake pipe ends to prevent brake fluid loss and contamination.
  13. Plug the modulator brake pipe openings to prevent brake fluid loss and contamination.

  14. Object Number: 927841  Size: SH
  15. Loosen the 2 insulator nuts on the brake pressure modulator valve assembly.
  16. Remove the brake modulator assembly from modulator bracket by pulling straight up.

Installation Procedure

Important: When installing a new brake modulator assembly, do NOT remove the shipping plugs from the pipe ports until after installation into the vehicle.

  1. Install the brake modulator assembly to the modulator bracket.
  2. Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 927841  Size: SH
  3. Tighten the 2 brake pressure modulator assembly insulator nuts.
  4. Tighten
    Tighten the nuts to 10 N·m (89 lb in).


    Object Number: 927833  Size: SH
  5. Remove the caps from the master cylinder brake pipe ends.
  6. Remove the plugs from the master cylinder ports on the modulator assembly.
  7. Connect the master cylinder brake pipes to the modulator assembly, in the same location as removed.
  8. Tighten the brake pipe fittings at the brake pressure modulator valve (BPMV).
  9. Tighten

        • Tighten the fittings first design, ISO flare, to 19 N·m (14 lb ft).
        • Tighten the fittings second design, double inverted flare, to 18 N·m (13 lb ft).
  10. Remove the caps from the caliper and wheel cylinder brake pipe ends.
  11. Remove the plugs from the caliper and wheel cylinder ports on the modulator assembly.
  12. Connect the caliper and wheel cylinder brake pipes to the modulator assembly, in the same location as removed.
  13. Tighten the brake pipe fittings at the brake pressure modulator valve (BPMV).
  14. Tighten

        • Tighten the fittings first design, ISO flare, to 19 N·m (14 lb ft).
        • Tighten the fittings second design, double inverted flare, to 18 N·m (13 lb ft).

    Object Number: 927847  Size: SH
  15. Connect the electrical connector to the EBCM.

  16. Object Number: 927845  Size: SH
  17. Reposition the TCM, if equipped, to the mounting bracket.
  18. Bleed the hydraulic brake system. Refer to Hydraulic Brake System Bleeding .
  19. Turn the ignition switch to the ON position. DO NOT start engine.
  20. Perform the Diagnostic System Check - ABS .
  21. Observe the feel of the brake pedal after performing the diagnostic system check. If the pedal now feels spongy, air may have been in the secondary circuit of the brake modulator assembly, which may have been introduced into the primary circuit. If the pedal feels spongy, perform the Antilock Brake System Automated Bleed Procedure .
  22. Remove the shop towel and discard into an approved container.