Anti-Lock Brake System: Operation: Notes
The EBCM is located in left rear storage compartment behind driver's seat. Wheel speed sensors relay information about wheel acceleration, deceleration and slip value. The EBCM controls braking by activating and deactivating electromagnetic modulator valve.
The modulator valve consists of 3 rapidly switching solenoid valves, two accumulator chambers and a return pump. The valves increase and decrease brake fluid pressure to each wheel (rear wheels are one circuit) to prevent wheel lock-up.
The modulator valve can supply only as much fluid pressure as applied by the driver through the master cylinder. The modulator valve alone CANNOT apply the brakes.
As a quick system test: When ignition switch is turned to ON position, Amber ANTI-LOCK warning light on instrument panel will illuminate. After engine is started, light goes out with battery warning light. If ABS warning light fails to go out or comes on while driving, a system fault is indicated.
The lateral acceleration switch, located within instrument panel beneath radio assembly, consists of 2 mercury switches in series. It determines if vehicle is cornering faster than a given curve speed. When speed is exceeded, one of two mercury switches opens to send a signal to the EBCM.