What is knock sensor 1 circuit malfunction bank 1 or 1 sensor mean?

Answer 1

knock sensor is a very sensitive small microphone usually on the engine block or sum times on the cylinder head , it listens for any pre detonation going on in your engine . pre detonation is nasty early combustion you dont want, if you get pre det it causes a pre knock sound which the knock sensor microphone detects.

your probly not getting pre detonation but thats what the sensor does 8)

"sensor 1 circuit" means the ecu has detected it cannot make connection to the sensor, the sensor could be dead or you could have a wiring issue to the sensor IE chaffed wire, bad connection at the plug ect.

Brett