A knock sensor detects abnormal vibrations characteristic of spark knock,and then signals the computer to retard ignition timing accordingly.Knock sensor tells the engine computer when one or more of your engine's cylinders are "knocking", that is, exploding the air/fuel mixture in a way that delivers less power and can be damaging to the engine if prolonged.

How to test the knock sensor:
1、Use manufacturer data to identify the knock sensor output circuit.
2、ConnectPicoScope channel Ato the Knock Sensor output circuit.
3、Minimise the help page and with the example waveform on your screenPicoScopehas
4、already selected suitable scales for you to capture a waveform.
5、Start the scope to see live data.
6、Simulate an engine knock bytapping lightly on the engine block with a metallic objectand observe your screen.
7、With your waveform on screen stop the scope.
8、Use the Waveform Buffer, Zoom and Measuring tools to examine your waveform.

Replacement for:
2003-2006 for Subaru Baja 2.5L
2003-2004 for Subaru Forester 2.5L
2003-2005 for Subaru Impreza 2.0L
2003-2004 for Subaru Impreza 2.5L
2002-2005 for Subaru Legacy 2.5L
2002-2006 for Subaru Outback 2.5L