Knock Control Unit
WARNING: This page is about a different car, the 1989 Ford Probe. However, it is still accessible from the selected car via links, so may be relevant.
This control unit is used on turbocharged engines only. It determines if signals produced by the knock sensor are due to pre-ignition or vibration. It filters the signal that is sent to the ECA. The ECA uses the signal to retard ignition timing. It is mounted on the firewall next to the BP sensor.