Q: How do the ABS Control Module and ABS Sensors work together to prevent wheel lock-up on Nissan Altima?
A: The Anti-lock Brake System (ABS) works in such a way as to ensure that vehicle steerability, directional stability as well as the optimum car deceleration under conditions of severe brake and on different types of road surfaces are maintained by merely checking the speed of rotation of each wheel and commanding the Brake Line pressure in order to avoid the wheel from locking. Actuator assembly consist of electrical hydraulic pump and solenoid valves for all wheel where the hydraulic pressure supplied by the pump charges reservoirs that are used to supply pressure during ABS and without brake line pressure supplied by solenoid valves. Sine wave current is produced by the speed sensors each at the wheels as the sensor rotors turn, The analog voltage signals produced are received by the ABS control unit where it is processed into a digital form to determine the speed at which the wheels are rotating. The control unit of ABS is located on the brake booster, and it analyzes signals from the wheel speed sensors to modulate hydraulic pressure so that the wheel can be unlocked in times of abnormal operations, though their normal working condition, it checks for any failure. At the beginning of the turn on the ABS symbol blinks, it should go off within a second of starting the engine and this tends to indicate that the ABS is operational. A self-test is conducted when the vehicle speed hits four mph, which creates a mechanical sound; if there is an occurrence of a problem, the ABS light will remain on, and in the control unit, there is a recipe of the problem.