Replacement modulators are shipped already filled and bled. In normal procedures requiring removal of the modulator, such as to replace the electronic brake control module (EBCM), air will not enter the modulator, and normal bleeding will be all that is needed.

If air enters the hydraulic modulator, or if an unfilled modulator is installed, use the brake bleeding program in the scan tool to bleed the modulator. Manual bleeding of the hydraulic modulator is not possible.

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

Notice: When adding fluid to the brake master cylinder reservoir, use only Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container. The use of any type of fluid other than the recommended type of brake fluid, may cause contamination which could result in damage to the internal rubber seals and/or rubber linings of hydraulic brake system components.

Important: The bleeding sequence is as follows: right rear, left rear, right front, and left front.

Important: Inspect the fluid level and add the fluid during the bleeding operation.

1. Raise the vehicle.



2. Remove the bleeder screw and cap.



3. Attach a transparent tube over the valve. Allow the tube to hang submerged in brake fluid in a transparent container.
4. Slowly push the brake pedal several times and hold the brake pedal.
5. Tighten the bleeder screw after loosening the bleeder screw and draining the fluid.

Important: Hold the brake pedal until tightening the bleeder screw.

6. Repeat steps 4 and 5 until all the air is removed.
7. Inspect the leaks for the bleeder screw.