Engine Knock Sensors?? [Archive] - Bimmerfest - BMW Forums

: Engine Knock Sensors??

01-08-2009, 08:34 PM
can someone please tell me what they do and how they can be tested?

01-08-2009, 08:46 PM
You could of just asked this in your first post....a quick search on google shows this http://www.yotatech.com/f116/how-test-knock-sensor-124269/ which states "the only real way to test a KS is with an o-scope." "The knock sensor measures for a VERY SPECIFIC frequency of sound." From what I read it just retards the timing if it is activated. Hope this helps.

bimmer dot info
01-09-2009, 08:11 AM
They listen for knock and the engine computer decides how much to retard the timing. This prevents knock (pre-ignition) which will kill an engine fairly quickly.