General Description; Anti–Lock Brake System (Abs) - Isuzu 1999 RODEO Workshop Manual

8D–149
WIRING SYSTEM
Anti–Lock Brake System (ABS)

General Description

The circuit consists of the starter switch, stoplight switch
EHCU wheel speed sensor, ABS warning light, BRAKE
warning light, and data link connector.
When the service brake is applied while in the running
mode, the EHCU (Electronic Hydraulic Control Unit)
judges which wheel is about to lock by using the wheel
rotation speed signals sent from the three wheel speed
sensors at the front wheels and rear differential. And the
brake fluid pressure applied to the four wheels is
controlled by the EHCU to prevent the wheels from
locking.
Based on the wheel rotation speed signals input from the
wheel speed sensor, the EHCU sends out signals to the
hydraulic unit to increase, maintain or decrease the brake
fluid pressure. The EHCU uses these signals to control
the fluid pressure which is applied to the front and rear
wheels.
Refer to Brake Control System in Brakes section in detail.