If the wheel is prone to blocking, i.e. the brake fluid pressure in the corresponding caliper is too high in relation to the traction force of the wheel on the road, the hydraulic system keeps the fluid pressure constant based on a signal from the control unit. This means that the pressure no longer increases despite the pedal being depressed. If there is still a risk of blocking, the brake pressure is reduced by opening the exhaust valve until the wheel starts to accelerate again, then the pressure is again kept constant. The rear wheels are steered together, the pressure in the system is determined by the rear wheel with the most slip.
If the wheel accelerates faster than a certain value, the pressure in the system rises again, however, not more than the total pressure of the entire system.
This process is repeated for each wheel until the gas pedal is released or the vehicle is in a state close to a stop (2-3 km/h).
The protective system provides automatic shutdown of the ABS when it fails (e.g. due to cable break) or too low voltage (battery voltage below 10.5V). In this case, the ABS warning lamp lights up while driving. The conventional braking system remains in service. When braking, the car behaves as if it did not have ABS. If the ABS warning light comes on while driving, the anti-lock braking system is disabled.
1 - main brake cylinder; 2 - brake force distributor; 3 - hydraulic unit; 4 - ABS control device; 5 - ABS relay; 6 - front speed sensors; 7 - rear speed sensors; 8 - front touch ring; 9 - rear sensory ring; 10 - diagnostic plug
1. Stop the car, turn off and start the engine again.
2. Check battery voltage. If the voltage is below 10.5V, charge the battery.
Attention! If the ABS warning light was on at the beginning of the trip and went out again after a while, this means that the battery voltage was initially too low, and then increased due to charging from the alternator.
3. Check that the battery terminals are securely tightened and have perfect contact.
4. Raise the car, remove the front wheels, check the electrical wires of the speed sensors for external damage.
5. Further checking of the ABS should be carried out in a workshop. The control unit registers the malfunctions that occur and stores them in memory. In MAZDA workshops, stored faults can be read from the memory via the diagnostic plug.
Attention! Disconnect the plug from the control unit before performing electric welding. Disconnect the plug only when the ignition is switched off.