Brake malfunction is a safety issue that can occur in Toyota Highlanders. It happens when the vehicle's braking system fails to work correctly, usually due to a problem with the brakes themselves. This can be caused by a number of things, such as worn brake pads, leaking fluid, or air in the lines. If your Highlander starts to experience brake problems, it is important to take it to a mechanic as soon as possible so that they can fix the issue and avoid any accidents.