Audi 80/Avant (B4)
since 1991-1995 release
Repair and operation of the car
+ Technical specification
+ System of production of the fulfilled gases
+ Cooling system
+ Fuel tank and fuel pump
+ Air filter and airintaking channels
+ System of injection
+ Transmission and transmission
+ Suspension bracket and steering
+ Brake system
- Anti-blocking system of brakes
Malfunctions of ABS
+ Wheels and tires
+ Body electrical system
+ System of ignition
+ Signaling devices
+ Devices and auxiliary devices
+ Heating and ventilation
+ Body elements
+ Search of malfunctions
It is located in a motor compartment at the left behind: the hydraulic block is between the brake pipeline from the main brake cylinder and the brake pipeline to wheel brakes. According to teams of an electronic control unit pressure in the brake system is supported to constants, decreases or created again. However this pressure cannot be higher than what is created in the main brake cylinder after pressing of a pedal of a brake by the driver. Regulation of pressure is carried out by four quickly we vklyuchayushchimitsya by valves with the electromagnetic drive – on one on a wheel.
Rotation frequency sensors
Frequency of rotation of each separate wheel is determined by the rotation frequency sensor (all their four pieces) and transfers this information to the control unit. In return the control unit gives team to the hydraulic block.
Electronic control unit
The control unit is located under back sitting at the left and processes the arriving signals from rotation frequency sensors. At the same time it operates the hydraulic block so that wheels were not blocked. Along with difficult processing of signals and the logic following this element the control unit contains also the scheme of blocking. With its help the device can check itself, distinguish external mistakes and control working tension. If malfunctions are established, ABS is disconnected, on the dashboard the control bulb lights up.
Three relays participate in work of ABS:
The models produced to 07.92 g.
By means of the main switch located on the panel of switches on the dashboard at the cars released till July of 92 g it is possible to disconnect ABS in order that in extreme road conditions it was possible to reach some reduction of a brake way. So, for example, if on the road filling brick is scattered or ice is covered with snow, when braking in front of tires