What indicates that brake pads may need replacement?

The presence of a squeaking noise when braking is a clear indicator that brake pads may need replacement. This noise is often caused by a built-in warning indicator, often referred to as a squealer, which is designed to alert the driver that the brake pads have worn down to a level requiring replacement. When the friction material wears down to a certain thickness, the metal backing of the brake pad comes into contact with the rotor, creating noise as a signal for maintenance.

While the other options listed—high fuel consumption, leaking oil, and low battery voltage—are indicative of different vehicle issues, they do not specifically pertain to the condition of brake pads. High fuel consumption relates to the engine or fuel system performance, leaking oil concerns the integrity of engine seals or gaskets, and low battery voltage reflects electrical system challenges. Therefore, the squeaking noise is a specific and direct symptom pointing to the need for brake pad replacement.