The brake system with ABS is double-circuit and diagonal. Strengthening in brake system is carried out by means of the vacuum amplifier.

Malfunctions of ABS influence brake system and strengthening in it. In case of malfunction of ABS it is necessary to reckon with change of brake effort. After fire of a control lamp of ABS back wheels when braking can prematurely be blocked.

Cars with ABS Mark 25 are not equipped with a mechanical regulator of brake forces. The special software in the control unit watches distribution of brake effort for a back axis.

Fig. 6.61 . ABS control unit

The control unit 1 and the block of hydraulics 2 form the uniform unit (fig. 6.61) .

Division is possible only in the removed condition. The hydraulic pump 3 cannot be disconnected from the hydraulics block.

New control units as spare parts have no coding. After installation they are necessary for coding.

Electric/electronic components

Fig. 6.62 . Electric/electronic components: 1–hydraulic ABS block; 2–ABS control unit; 3–sensor of pressure of brake system; 4–the sensor of pressure of strengthening in brake system; 5–vacuum pump of brakes; 6–control lamp of ESP and ASR; 7–control lamp of ABS; 8–control lamp of brake system; 9–key of ASR and ESP systems; 10-block of ESP sensors; 11-sensor of an angle of rotation of a steering wheel; 12-the diagnostic I will corrode; 13-switch of a stoplight and sensor of a pedal of a brake; 14-forward right sensor of number of turns / forward left sensor of number of turns; 15-wheel wheel bearing / nave assembled; 16-back right sensor of number of turns / back left sensor of number of turns; 17-wheel wheel bearing / nave assembled

Electric / electronic components of ABS system are shown on fig. 6.62 .

Display of faults by control lamps

If the control lamp of ABS 3 does not die away after inclusion of ignition and end of a control cycle, causes of defect can be the following:

– tension of less than 10 In;

– there is a malfunction of ABS.

At defect of ABS b the anti-blocking system remains disconnected, and the brake system remains in an efficient condition;

Fig. 6.63 . Diagnostic socket

– after the last start of the engine there was a temporary failure of the sensor of frequency of rotation.

In this case the control lamp of ABS automatically dies away at restart of the engine and the subsequent movement with a speed 2,75 km/h are higher;

– connection from a combination of devices to the ABS control unit is broken;

– the control lamp of ABS is faulty.

Fig. 6.64 . Control lamps

Control lamp of ABS and control lamp of brake system

If the control lamp of ABS dies away, and the control lamp of brake system burns, causes of defect can be the following:

– level of brake liquid the too low.

After inclusion of ignition three warning signals are audible.

– malfunction of conducting to a control lamp of brake system K118

If the control lamp of ABS 3 and a control lamp of brake system 4 – malfunction of ABS system burn. In case of malfunction of ABS it is necessary to reckon with change of brake effort.

ATTENTION After fire of a control lamp of ABS and a control lamp of brake system back wheels can prematurely be blocked when braking.

Control lamp of ESP and ASR

If the control lamp of ESP and ASR does not die away after inclusion of ignition and end of a control cycle, causes of defect can be the following:

– there is a malfunction which touches only ASR/ESP. Systems of safety of the ABS/EDS and EBV car remain completely in an efficient condition. Interrogate memory of malfunctions;

– short circuit on plus in the ASR/ESP button;

– short circuit on mass of management of a control lamp of ESP and ASR;

– connection from a combination of devices to contact of 31 ABS control units is interrupted;

– the ASR/ESP system was disconnected by the ASR/ESP button.

If the control lamp of ESP and ASR blinks during movement, ASR or ESP systems are in a regulation mode.

Control lamp of brake system

If the control lamp of brake system after inclusion of ignition does not die away, it can have following reasons:

– the parking brake is involved;

– the switch of a control lamp of brake system is faulty or incorrectly adjusted;

– there is a mistake in conducting. Make electric check.

The contact switch of the parking brake hands over to the ABS control unit information on that, is involved or not the parking brake. At the involved parking brake negative impact is had on regulation of ESP.

Control lamp of wear of brake shoes

If the control lamp of wear of brake shoes does not die away through 3 спосле inclusions of ignition or lights up during movement, the following malfunctions can be the reason of it:

– brake slips can be worn-out.

Check brake shoes of lobbies and back wheels. Replace blocks if they are worn-out;

– there is a malfunction in conducting.

Removal and installation of components of ABS system on forward and back axes

Fig. 6.65 . The ABS components on a forward axis: 1–sensor of frequency of rotation of ABS; 2–a bolt with an internal shestigrannik, 8 N · m; 3–a wheel nave with the bearing (bearing knot); 4–power shaft

The ABS components on a forward axis are shown on fig. 6.65 .

Removal and installation of the sensor of frequency of rotation on a forward axis

Lift the car.

Fig. 6.66 . Shtekernoye connection

Separate shtekerny connection of 1 cable of the sensor of frequency of rotation and the sensor of frequency of rotation (fig. 6.66) .

Turn out a bolt 2 of the case of the wheel bearing.

Take the sensor of frequency of rotation of ABS from the case of the wheel bearing.

Installation

Before installation of the sensor of number of turns clear an opening and to put a little plastic greasing on all diameter

Insert the sensor of frequency of rotation into an opening of the case of the wheel bearing and tighten a bolt the moment of 8 N · m.

Connect the sensor of frequency of rotation to a sensor cable.

Removal and installation of components of ABS system on a back axis

Fig. 6.67 . The ABS components on a back axis: 1–sensor of frequency of rotation of ABS; 2–a bolt with an internal shestigrannik, 8 N · m; 3–wheel wheel bearing/nave assembled; 4–power shaft

The ABS components on a back axis are presented fig. 6.67 .

Removal and installation of the sensor of frequency of rotation on a back axis

Lift the car.

Fig. 6.68 . Shtekernoye connection

Separate shtekerny connection of 1 cable of the sensor of frequency of rotation and the sensor of frequency of rotation (fig. 6.68) .

Turn out a bolt 2 of the case of the wheel bearing.

Take the sensor of frequency of rotation of ABS from the case of the wheel bearing.

Before installation of the sensor of number of turns clear an opening and to put a little plastic greasing on all diameter

Insert the sensor of frequency of rotation into an opening of the case of the wheel bearing and tighten a bolt the moment of 8 N · m.

Connect the sensor of frequency of rotation to a sensor cable.