Rio L4-1.6L (2004)
Hydraulic Control Assembly - Antilock Brakes: Description and Operation
HECU (HYDRAULIC & ELECTRICAL CONTROL UNIT)
The ABS control unit performs the following functions:
^
Controls the ABS
^
Calculates vehicle speed
^
Self-diagnostics: Stores malfunction codes, performs ABS control unit self-diagnostic and fail-safe functions with two separated microprocessors.
The ABS control unit continuously checks locking of each wheel and controls each valve to adjust brake fluid pressure if required. The ABS control
unit also checks that components are working properly and stops ABS if a malfunction is detected. Then, it is operated as a standard brake system.
SPEED SENSOR
STRUCTURE
The speed sensor detects wheel rotation and consists of a permanent magnet and pickup coil. Sensors for the front wheels are attached to drive
shaft and rear hub spindle for the rear wheel.
OPERATION
