VW Passat B5

since 1996 release

Repair and operation of the car

Foltsvagen Passat B5
+ Maintenance instruction
+ 1. Maintenance
+ 2. Engines
+ 3. Cooling system
+ 4. Fuel system
+ 5. Engine management
+ 6. Exhaust system
+ 7. Transmission
+ 8. Running gear
+ 9. Steering
- 10. Brake system
   10.2. General information
   10.3. ABS/EBV/EDS/ASR/ESP systems
   10.4. Check of the vacuum amplifier of brakes
   + 10.5. Replacement of front brake shoes
   10.6. Replacement of back brake shoes
   10.7. Check of a brake disk
   10.8. Brake disk
   10.9. Pumping of the hydraulic brake system
   + 10:10. Brake pipelines and hoses
   10:11. Stoplight switch
   10:12. Lever of the emergency brake
   10:13. Adjustment of the emergency brake
   + 10:14. Cable of the emergency brake
   10:15. Main malfunctions of brakes
+ 11. Body
+ 12. Heating, ventilation
+ 13. Electric equipment

10.3. ABS/EBV/EDS/ASR/ESP systems


ABS. Anti-blocking system of brakes

Efficiency of braking the greatest, when coupling of the tire with the surface of the road maximum. In the course of braking the tire slides on a surface, and the district speed of a wheel becomes less than the speed of the car.

Sliding minimum (0%) when the wheel slides freely, and maximum (100%) when the wheel is blocked. Maximum efficiency of braking is reached when sliding makes 15%. This size also allows to keep stability and controllability of the car.

The role of anti-blocking system consists in restriction of pressure created in hydraulic system of brakes so that the size of sliding kept about the optimum size (15%). Action of this system has to be immediate and separate for each wheel. The system has to answer immediately each change of a surface (coupling coefficient) and load of the car.

In anti-blocking system of TEVES (ATE) in one unit functions of power supply, the drive of brakes and the vacuum amplifier, and also management of anti-blocking of wheels are carried out. The hydraulic block is installed instead of the serial installed vacuum amplifier with the built-in main brake cylinder. The ABS installation is possible only at the plant at production of the car and cannot be established in addition. The anti-blocking system interferes with blocking of wheels at sharp braking. Thanks to it the brake way decreases, especially at low coupling with a paving at a rain and snow. Force of adhesion between wheels and the road in this case is more when when braking a wheel continue rotation. In addition even at full braking the car remains operated. RPM meters, on one on each wheel, measure the speed of rotation of a wheel. On signals from wheel RPM meters in the electronic operating block the average speed which is approximately corresponding to the speed of the movement of the car is calculated. Comparing the speed of rotation of each separate wheel to the average calculated speed, the electronic block defines a condition of slipping of a separate wheel and by that establishes what wheel is in a preblocking state.

When one of four sensors of speed of rotation transmits a signal of blocking of the corresponding wheel, immediately the electronic actuation device gives a closing signal to I correspond to the shchy inlet electromagnetic valve which immediately blocks supply of brake fluid via the brake pipeline to a brake of this wheel – force of braking remains to a constant. If nevertheless sliding continues, then the final valve and pressure in hydraulic system of this brake opens decreases – the wheel is not braked (surplus of brake fluid comes back to a tank). As soon as the wheel starts over again rotating, at once there is an opening of the inlet valve and closing of the final valve. Pressure increases in a contour, and the wheel is again braked.

Such cycle of braking and free rotation of a wheel occurs very quickly (several times in a second) and proceeds to a stop cars or to a brake pedal otpuskaniye.

This process repeats at sharp braking separately for each wheel until the pedal of a brake is released or at reduction of speed of the car to 2–3 km/h. The driver defines work of ABS on a brake pedal pulsation.

The system of emergency shutdown provides shutdown of the ABS system at any malfunction or at low voltage in electric network of the car (lower than 10B). The electronic actuation device performs also avtodiagno stichesky function, warning the driver fire of a control bulb about registration of malfunction of electric chains or elements of anti-blocking system. At the faulty ABS system of a brake, nevertheless, are serviceable and function as if this system is not in the car.

EBV. The electronic distributor of brake effort on back wheels

The electronic distributor of brake effort performs functions механическо го pressure regulator, but works more precisely and has wider range of adjustment. At the movement of the car on a straight line supply of brake fluid to brakes of back wheels is completely open. For ensuring stable passing of turns with braking supply of brake fluid to back brakes is limited. On the basis of signals of sensors of rotation of wheels of the ABS system the EBV control unit defines when the car moves in turn. When passing by the car of turns the brake effort transferred to back wheels decreases therefore the probability of a drift of the car decreases.

EDS. Electronic blocking of differential

Being addition to the ABS, EDS elements reduces torque transmission of the engine under adverse traffic conditions, especially on rises and at accelerations of the car, eliminating pro-slipping of one of driving wheels. Thanks to mechanical blocking of differential improvement of torque transmission as at the same time the party with great value of coefficient of friction can transfer bigger torque is reached.

The electronic control unit obtains information from ABS sensors on the speed of rotation of driving wheels and constantly compares them. In the presence of a difference of speed over about 110 rpm of EDS joins automatically and reduces torque transmission by the revolving wheel until it does not have approximately the same speed, as not slipping wheels. Thanks to such management reaches ся that to a wheel with the best conditions of coupling with the road the increased torque is transferred. EDS is automatically disconnected at a speed of the movement of the car higher than 40 km/h, and also when passing turns and when overheating brakes.

ASR. System of reduction of torque of the engine transferred to driving wheels

Reduction of torque at skidding of both driving wheels is carried out by deceleration of power of the engine. In this case engine capacity is limited so that only the torque necessary for the movement of the car was transferred.

The ASR system has to be always included. Only in certain exceptional cases when pro-slipping of wheels is desirable, it is preferable to switch off system.

ESP. Electronic system of stabilization

By means of system of stabilization control of dynamics of the car in the limit modes is exercised, for example, when overcoming turns at a high speed. Danger of demolition or a drift of the car significantly decreases at all possible conditions of a paving.

In electronic system of stabilization the anti-blocking system of brakes and probuksovochny systems are integrated. In electronic system of stabilization are in addition measured the speed of movement of a body around a vertical axis, size of accelerations in the cross plane, pressure in system of the drive of brakes and an angle of rotation of the operated wheels. On the basis of the operated wheels given about an angle of rotation and speed of the car defines that direction in which the driver of the car intends to move, and it is constantly compared with the actual behavior of the car. At a nonagreement of these factors when demolition or a drift of the car begins, the system of stabilization automatically brakes a certain wheel.

With malfunction the system of electronic control is automatically disconnected, at the same time on a combination of devices control lamps light up. In this case the brake system works in the usual mode.

If during the movement control lamps of ABS and EBV light up, keep in mind that at sharp braking there can be a blocking of back wheels.

Fire of one or several control bulbs during the movement signals about shutdown of system. At the same time it is necessary to perform the following operations.
1. Stop the car, switch off and start the engine.
2. Check accumulator tension. If it lower than 10,5 In, charge the accumulator.

If the control lamp of ABS burns at the beginning of a trip, and then dies away, it demonstrates that tension was an admissible limit for ABS work, but then raised as a result of operation of the generator.

3. Check a condition of plugs of the accumulator.
4. Lift the car, remove wheels and check serviceability of an electrical wiring of sensors of speed of rotation of wheels.
5. If malfunction is not eliminated, then further check needs to be made at service station.