GM Service Manual Online
For 1990-2009 cars only

Caution: Brake fluid may irritate eyes and skin. In case of contact, take the following actions:

   • Eye contact - rinse thoroughly with water.
   • Skin contact - rinse with soap and water.
   • If ingested - consult a physician immediately.

Caution: To help avoid personal injury due to poor braking, DO NOT tap into the vehicle's brake hydraulic system to operate a trailer brake system.

Caution: Remove all the air from the hydraulic brake system anytime the hydraulic brake system is opened for repair. The entire bleeding procedure must be followed. Failure to remove all the air in the hydraulic brake system will result in reduced braking performance and possible personal injury.

Caution: Certain components in the Antilock Brake System are not intended to be serviced individually. Attempting to remove or disconnect certain system components may result in personal injury and/or improper system operation. Only those components with approved removal and installation procedures in Antilock Brakes or Antilock Brakes (ABS) with Traction Control System (TCS) should be serviced.

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/master cylinder assembly.

Notice: The following are general precautions which should be observed when servicing the antilock brake system, traction control system and/or other vehicle systems. Failure to observes these precautions may result in antilock brake system damage. Refer to the CAUTIONS and NOTICES in this section.

Notice: DOT 5 silicone brake fluid should never be used in the ABS Brake System. Excessive wear of brake components and other conditions can occur from using DOT 5 silicone brake fluid.

Notice: Do not touch the electrical connections and pins, or allow them to come in contact with brake fluid, as this will damage the EBCM.

Notice: Power steering fluid and brake fluid must not be mixed. If brake seals contact steering fluid or steering seals contact brake fluid, seal damage will result.

Notice: The following service procedures shall be performed only after the ABS brake modulator/master cylinder assembly has been removed from the vehicle. Do not perform these procedure with the unit installed on the vehicle. Complete overhaul of the ABS brake modulator/master cylinder assembly is not authorized, only the following steps. These steps will break the unit down into major components for replacement purposes.

    • Unplug the following components before performing electric welding procedures:
       - The EBCM harness connector
       - The brake pressure modulator valve assembly connector
    • Note the routing, position, mounting and location of the following ABS components:
       - Wiring
       - Connectors
       - Clips
       - Brackets
       - Antilock components are extremely sensitive to EMI (Electromagnetic Interference).
       - Proper mounting is critical when servicing ABS components.
    • Do not disconnect the battery from the electrical system with the engine running.
    • When disconnecting the EBCM connector, turn the ignition switch to the OFF position.
    • Do not hang the suspension components by the wheel speed sensor cables.
        Hanging the components by the sensor cables may damage the sensor cables.
    • Do not force the wheel speed sensors into place. Push the sensors into place by hand only.
    • During painting work, do not subject the EBCM to temperatures exceeding the following specifications:
       - 95°C (203°F) for brief periods of time
       - 85°C (184°F) for lengthy periods of time (about two hours)
    • Use the following guidelines when filling the master cylinder:
       - Use only Supreme 11 (GM P/N 1052542) or equivalent DOT 3 brake fluid.
       - Do not use a container that has been used for petroleum based fluids.
       - Petroleum based fluids will cause swelling and distortion of rubber parts in the hydraulic brake system.
       - Do not use a container that is wet with water.
       - Water will mix with brake fluid. Mixing brake fluid and water lowers the boiling point.
       - Keep all fluid containers capped in order to prevent contamination.
    • Use the Scan Tool diagnostic tester in order to inspect the entire ABS system after replacement of any of the following components or any other ABS work:
       - The brake pressure modulator valve
       - The EBCM
       - The wheel speed sensors
       - The wring harnesses
       - Refer to Diagnosis in Antilock Brakes.
       - The above precautions are not exhaustive and must be followed when working on an ABS equipped vehicle.
       - Become familiar with the ABS and how the ABS may be interrelated to other components on the vehicle when performing service work.