GM Service Manual Online
For 1990-2009 cars only

Important General Information

       Important: The ABS control unit may not be separated from the hydraulic modulator in vehicles with hill start assistance (HSA). If there is a fault, the complete hydraulic modulator unit with ABS control unit must always be replaced.

    • Before replacing the ABS control unit, Tech 2 must be used for determining whether the fault can be allocated unambiguously to the ABS control unit.
    • The ABS control unit may not be used again after suffering mechanical impact loading (collision, impact).
    • When replacing the ABS control unit, take particular care with regard to absolute cleanliness. Only lint-free cloths may be used. After removal, the outside of the hydraulic modulator must be cleaned with cleaning agent which does not contain mineral oil.
    • The connections on the hydraulic modulator must be sealed immediately with suitable plugs after detaching the brake lines.
    • When the ABS control unit has been removed, care must be taken that no liquids can run into the plug and into the inside of the ABS control unit.
    • Never work with compressed air in the area of the hydraulic modulator with the brake system open.
    • The electronic printed circuit board is exposed when the ABS control unit has been detached. The electrical contact surfaces in the ABS control unit must not be touched with the hand or with other objects.
    • No moisture or dirt particles may penetrate into the inside of the ABS control unit.
    • Ensure that the ABS MK70 has all the seal rings complete. Missing seal rings lead to a short circuit caused by moisture penetration.