Table of contents: Anti-lock braking system (ABS) and… ↓ ESP system and ASR function ↓ Parking brake ↓
The brake system of the cars in question is equipped with a vacuum booster, which allows for braking with a certain intensity to apply less force to the brake pedal than would be required without the booster. If the booster does not work (when the engine is not running or for another reason), the braking system remains in good working order, but you will need to press the brake pedal with significantly more force, and the braking distance will increase.
Note: Intensive use of disc brakes promotes their self-cleaning. Therefore, low mileage, long downtimes and low load of the brake system create favorable conditions for the development of corrosion of brake discs and contamination of brake pads. When braking, discs covered with corrosion cause a vibration effect, which is often impossible to eliminate even by prolonged pressing of the brake pedal.
With the engine off, each time you press the brake pedal, the additional braking force is reduced, so do not press the brake pedal without a need to do so when the brake booster is not working (for example, when keeping a car on a slippery road).
In case of brake failure while driving, braking is permitted using the parking brake (see subsection below), however, it should always be remembered that the braking distance in this case will be much longer than the braking distance when using the service brakes.
Caution: Using the parking brake while the vehicle is moving at high speed may cause loss of vehicle control, so if you must use the parking brake to stop, use extreme caution.
Caution: Do not keep your foot on the brake pedal while the vehicle is moving, as this will cause the brakes to heat up and wear out prematurely, and will increase the braking distance. When driving downhill, do not use the brakes for too long, instead use engine braking by manually shifting to lower gears. After driving in the rain, or after driving through water, dry the brakes by lightly pressing the brake pedal and holding it until the brake efficiency returns to normal.
The braking system is divided diagonally into two independent hydraulic circuits. If one of the circuits fails, (for example, as a result of a breach in sealing, this is felt by the softness of pressing the pedal) the second continues to function in normal mode, providing adequate braking of the car, but with an increased braking distance. A low brake fluid level is indicated by the inclusion of the corresponding K/L in the instrument cluster (see Section 15).
Anti-lock braking system (ABS) and its functions: EDS and BAS
The ABS system constantly monitors the rotation speed of the vehicle's wheels and prevents them from locking by repeatedly changing the hydraulic pressure in the brake system. Thus, even with the brake pedal fully depressed, the vehicle remains controllable. ABS is activated automatically each time the engine is started. The serviceability of the ABS is indicated by the corresponding indicator lamp in the instrument cluster (see Section 15), - this lamp lights up when the ignition is turned on and goes out after the ABS self-diagnosis has been successfully completed. If the K/L does not go out, then the ABS is faulty, but the working brake system may function normally.
During ABS operation (this can be felt by the pulsation of the brake pedal) do not change the amount of pressure on the brake pedal, as this will prevent the ABS system from operating at maximum efficiency. Remember the following precautions:
- even with an ABS system, the car cannot be stopped instantly - keep a safe distance;
- always reduce speed when turning corners, as the ABS system cannot prevent an accident at high speeds;
- when braking on an uneven road using ABS, the braking distance may be longer than without ABS;
- do not neglect general road safety rules.
If you press the brake pedal sharply, the Brake Assist function (BAS) is activated, which automatically uses all the capabilities of the ABS system to stop the car as quickly as possible. Do not change the force of pressure on the brake pedal, as this will prevent the ABS system from working with maximum efficiency. If the ABS is faulty, the BAS function does not work.
The distribution of torque between the drive wheels is carried out by the electronic differential function. (EDS). If an increased rotation speed of one of the drive wheels is detected (for example, if it is on a slippery shoulder), this wheel is braked and more traction is transmitted to the other wheel. This function operates at speeds over 40 km/h for front-wheel drive models or up to 80 km/h for all-wheel drive models. If EDS is triggered when starting off, continue to press the gas pedal until the car starts moving. If the brakes overheat, EDS is temporarily disabled and then turned on automatically.
ESP system and ASR function
The vehicle's electronic stability program (ESP) prevents the drive wheels from losing traction when starting off or accelerating sharply. ESP also recognizes driving conditions that could lead to a decrease in stability (oversteer or understeer), and keeps the car on course by reducing engine power and braking individual wheels. The ESP system uses the ABS system, several additional sensors and the engine management system.
Note: ESP cannot operate outside of physical limits, so you should not rely entirely on the operation of this system.
The anti-slip regulation (ASR) function prevents the drive wheels from slipping during acceleration by adjusting the traction force by reducing engine speed. For ASR to function properly, the same tires must be installed on all wheels.
ESP is activated every time the engine is started. To deactivate and reactivate ESP, use the "ESP" button in the key block (12 in illustration 14.1) of the central console. The ASR function is switched off simultaneously with the ESP. To maintain the vehicle's stability at the required level, try to switch the ESP system back on as soon as possible. Brief switching on of the ESP may be advisable in the following situations:
- when overcoming a snowy climb;
- when driving through slush or deep snow;
- when driving out of deep snow or loose ground with a rocking motion;
- when driving with snow chains.
Parking brake
To prevent a parked vehicle from rolling away, a hand-operated parking brake is used. The parking brake lever is located in the center console, between the seats (24 in illustration 14.1). When the lever is cocked, the rear wheels are locked and the corresponding K/L light in the instrument cluster lights up. The brake lights do not light up. If you try to move off with the parking brake cocked, an additional sound signal and warning message are heard.
To release the parking brake, press the button on the end of the lever, pulling it up slightly if necessary, and lower the lever.
To prevent corrosion and one-sided braking, apply the parking brake lightly from time to time before stopping at a traffic light when traffic conditions permit.