Based on signals from the wheel speed sensors, the ABS controller causes the control valve assembly to ________

The ABS (Anti-lock Braking System) controller utilizes signals from wheel speed sensors to monitor each wheel's rotational speed. This information is critical for preventing wheel lock-up and maintaining vehicle stability during braking. When the system detects that a wheel is about to lock up—typically due to excessive braking force or slippery road conditions—it can engage the control valve assembly to manage hydraulic pressure.

The correct answer reflects that the ABS controller has multiple functions regarding hydraulic pressure: it can maintain hydraulic pressure to allow for effective braking, release hydraulic pressure when it detects a potential lock-up situation, and increase brake pressure when necessary to maximize braking force without causing wheel lock-up. Therefore, all these functions are essential for the overall operation of the ABS, making the option that states "all of the choices are correct" accurate and comprehensive in describing the system's capabilities. This multifunctional approach is what helps ensure that the vehicle retains traction and stability during braking.