What does 'Knock sensor high input' mean on a 2000 subaru impreza 2.5rs?

A 'knock sensor high input' error on a 2000 Subaru Impreza 2.5RS indicates that the engine control unit (ECU) is detecting a higher-than-normal voltage signal from the knock sensor. This sensor monitors engine vibrations to detect knocking or pinging, which can indicate pre-ignition or detonation issues. A high input may suggest a faulty sensor, wiring issues, or excessive engine noise, potentially leading to performance problems or engine damage if not addressed. It's advisable to diagnose the sensor and related components for proper function.