Had a strange experience with a knock sensor on my 2000 Tacoma 2.4L. Last Friday a car pulled out in front of me so that I had to slam on the brakes. Later I noticed the check engine light was on. Maybe a coinceidence?? Saturday a local Advance Auto diagnosed the check engine light as an open or short in the knock sensor circuit. I measured the resistance of the knock sensor at 160 ohms.
When I and my son removed the sensor it was extremely tight. It gave out a very loud crack. Before taking it to get a new one I checked the resistance, it was now open! !
Reinstalled it and reset the check engine light and the truck runs great without a check engine light. It has run two days, about 350 miles, and runs fine.
Ideas or explaniations please..............Jay