Wheel Circuit Valve Operation

Early Production ABS Operation

Each of the four wheel circuits includes a solenoid valve. The valves have three positions to allow for pressure build, pressure hold, and pressure reduce modes during anti-lock operation. The amount of current flowing through the valve solenoid coil determines the position of the valve. Current flow through the valve coil is controlled by the Anti-lock Brake Control Module (ABM). During normal braking, the valves are not activated.