System ABS (Antilock Braking System)
On cars Sharan is installed as standard equipment the anti-lock system is manufactured by ITT Teves.
The ABS system enhances the active safety of the car and prevents the wheels from locking under heavy braking. Thus the car to a full stop shall be controllable without skidding.
The structure includes standard ABS braking system, the wheel speed sensor, a hydraulic unit, an electronic control unit (ECU-ABS) and electrical wire harness.
Wheel speed sensor ABS system transmit information in the form of an electric current alternating voltage of frequency of rotation of the wheels on the ABS-ECU. Speed sensors located on the front wheel steering knuckle and the rear wheels - in the journals.
ABS-ECU by signals from the four wheel speed sensors measure acceleration, deceleration or the slip of each wheel. Comparing the speed of each wheel with an average speed of all wheels, the ABS-ECU determines the degree of slip of the individual wheels and thus can set a time when one of them comes close to the block, and based on this data outputs control pulses to the solenoid valves of the hydraulic unit. Once one of the wheels suitable for blocking, the brake fluid pressure in its caliper is too high with respect to tire adhesion. The hydraulic system is under the influence of the control signals maintains brake fluid pressure stable. This means that the pressure in the caliper does not increase further even if the brake pedal. If the danger of locking is maintained, thanks to the opening of the exhaust valve, the pressure is reduced, but only to the point where the wheel again begins to accelerate more, and then again the pressure is kept constant.
If the wheel starts to spin faster, the ABS-ECU sends a signal to the pressure increase, but not above the total pressure in the brake system. The driver feels the effects of ABS pulsing of the brake pedal and the hydraulic characteristic of the sound of the engine compartment that signals him moving in the boundary conditions.
Hydraulic unit is mounted on the brake line after the brake master cylinder. Each of the four hydraulic unit suitable for pipes installed solenoid valve that removes the brake fluid to the electric pumps, which ensures braking pressure in the line of a particular wheel.
When a system fault ABS-ECU ABS stops the production of the control pulses, and stays in the instrument cluster indicator lamp ABS. Failure of the ABS system allows the car to move, but requires more attention to the speed of traffic and road conditions, as management efficiency drops sharply.
All work on the system of ABS held with the ignition off and remove the "-" terminal of the battery. Before working with welding equipment, unplug the plug connector ABS-ECU.
Check ABS, repair of the valve block, ABS-ECU or piping is to the service station.