ABS prevents the wheels from locking during sudden braking, so the car remains controllable. The driver feels the system's operation by the pulsation of the brake pedal and the noise of the hydraulic unit located in the engine compartment. A safety switch in the electronic control unit ensures that ABS is switched off if a malfunction occurs (for example, when a wire breaks) or if the battery voltage is too low (less than 10.5 volts) — the ABS indicator lights up on the instrument panel. When ABS is turned off, the regular braking system continues to function.
In this case, the car behaves as if ABS was not installed on it. After the ignition is turned on, ABS automatically checks for faults. After about 3 seconds, the indicator on the instrument panel should go out. If the indicator remains on longer or lights up while driving, you must perform the following actions.
Stop the car quickly, turn off the engine and start it again.
Check the battery voltage. If the voltage is below 10.5 volts, the battery needs to be charged.
Raise the car, remove the wheels, check the electrical wires to the wheel speed sensors for external damage (grinding). Other checks must be carried out in a workshop. The fault codes recorded by the control unit must be read out there using a diagnostic device and then specifically eliminated.
Caution: Before carrying out welding work using an electric welding machine, it is necessary to disconnect the plug connector of the ABS electronic control unit. The plug must be disconnected only with the ignition off. When carrying out painting work, the control unit may be heated to a temperature of no more than +85°C.
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