What indicates that ABS may not be functioning correctly?

A warning light coming on is a key indicator that the Anti-lock Braking System (ABS) may not be functioning correctly. In most vehicles, the ABS is equipped with a warning light on the dashboard that activates when there is an issue with the system. This can indicate various problems, such as a malfunction in the ABS control module, issues with the wheel speed sensors, or low brake fluid levels.

Recognizing the significance of this warning light is crucial because it alerts the driver to the fact that the technology designed to help maintain control during braking may not be operational. Understanding the implications of an inoperative ABS system is essential for safety, as it could affect handling and stopping capabilities, especially in slippery conditions where locked wheels can lead to skidding.

While other indicators like a grinding noise, excessive brake pedal pressure, or a vibrating steering wheel can suggest different issues related to the braking system or vehicle performance, they are not specific to the ABS. Thus, when the ABS warning light illuminates, it directly points to potential failures within the ABS itself, making it the correct answer in this context.