My 99 Legacy 2.2L has about 80K miles on it. Recently the Check Engine Light started coming on now and then, especially when the weather turns from "seasonal" for northern US to "freakishly warm", i,e. above 50 degrees.
I've removed and inspected the knock sensor visually, and detect no cracks or other obvious damage.
I have traced out the wiring, and I know I need to do some electrical checks. Verify no grounds, or shorts in signal or shield wiring, nominal voltage 2.8 volts at ECU, and some where I read there is a resistance spec for the sensor itself, somewhere above 500 K ohms.
