Anti-Lock Brake System: Description

Saab Mark IV Anti-Lock Brake System (ABS) has 3 main components: 4 wheel sensors, hydraulic unit (including valve block assembly) and an Electronic Control Unit (ECU). System is a dual-circuit, 4-port, braking system.

Signals from 4 wheel sensors are sent to ECU, which continuously monitors speed, acceleration and deceleration of wheels, road speed, and tire slip. If wheel is about to lock up, ECU sends signals to solenoid valves for wheel concerned, modulating pressure in brake circuit to provide optimum braking.