Knock Sensor tests - 90 Camry V6

camry
sensors

#1

I’ve got a 90 Camry with the 2.5L V6, showing a Check Engine code of 52, Loss of Knock Sensor Signal. I tried cleaning up the contacts, but still get the Signal Loss code. Are there any tests to determine whether the knock sensor is bad? Or should I go use the process of elimination to first rule out the wiring by establishing continuity to the ECM, and then assuming it must be a bad sensor? What causes them to go bad?



(The knock sensor came on after the car was sitting for a week while I replaced the right side tie rod end, the right side lower control arm, both half-axles, the rotors and pads, and the power steering pump hose. Because there was congealed grime from leaky power steering fluid everywhere, I was more than a little liberal with the Gunk Engine Degreaser.)



(Okay, it was more like three weeks.)


#2

Or is what I’m looking at NOT the knock sensor? It’s SOME kind of sensor, right next to the #1 injector connector. The wire disappears into the main intake manifold wiring harness.

A Chilton book has one diagram covering both the 2.5-liter and the 3-liter V-6’s: the diagram shows 2 knock sensors, located roughly by the #3 and #4 cylinders. My 1990 Toyota Camry book (volume 2) shows only one knock sensor, but I’m looking at the electrical circuit diagrams, not a component locator view of the engine management system, which would be in volume 1. Which I don’t have. Yet.


#3

A timing light can be used to determine if the knock sensor is functioning. Connect the timing light, and with the engine idling, tap on the engine with a wrench near the knock sensor. If the knock sensor is functioning, you’ll see the timing marks change with the timing light.

Tester