Four Wheel ABS Hydraulic Control Unit (HCU)

WARNING: Use of any other than approved DOT 3 brake fluid will cause permanent damage to brake components and will render the brakes inoperative.

WARNING: Brake fluid contains polyglycol ethers and polyglycols. Avoid contact with eyes. Wash hands thoroughly after handling. If brake fluid contacts eyes, flush eyes with running water for 15 minutes. Get medical attention if irritation persists. If taken internally, drink water and induce vomiting. Get medical attention immediately.

CAUTION: Brake fluid is harmful to painted or plastic surfaces. If brake fluid is spilled onto a painted or plastic surface, immediately wash it with water.

CAUTION: Do not allow the master cylinder to run dry during the bleeding operation. Keep the master cylinder filled with the specified brake fluid. Never use brake fluid that has been drained from the hydraulic system.

Note: This procedure only needs to be performed if a new 4-wheel anti-lock brake (4WABS) hydraulic control unit (HCU) has been installed or if the HCU lines have been opened.





1. Clean all dirt from and remove the brake master cylinder filler cap, and fill the brake master cylinder reservoir with the specified brake fluid.





2. Connect a clear waste line to the RH rear bleeder screw and the other end in a container partially filled with recommended brake fluid.
3. Loosen the RH rear bleeder screw until a stream of brake fluid comes out. While the assistant maintains pressure on the brake pedal, tighten the RH rear bleeder screw.
- Repeat until clear, bubble-free fluid comes out.
- Refill the brake master cylinder reservoir as necessary.








4. Tighten the RH rear bleeder screw, and disconnect the waste line.





5. Repeat Steps 2, 3 and 4 for the LH rear bleeder screw, the RH front disc brake caliper bleeder screw, and the LH front disc brake caliper bleeder screw, in that order.





6. Connect the scan tool DCL cable adapter into the vehicle data link connector (DLC) under the dash, and follow the scan tool instructions.
7. Repeat the system bleed procedure as outlined in Steps 1 through 5.