Suburban Knock Sensor
Did a little work on this Suburban the other day. It came in with a knock sensor code and a lean bank 2 code. The motors are prone to having water get into the rear knock sensor cavity and kill the sensor. I figured this probably was causing the lean code as well (turns out that is something else, likely a small vacuum leak somewhere).
The old 5.3L v8.
Top cover removed. The intake needs to be lifted up enough to get to the rear sensor.
For picture purposes, here is the front knock sensor. It sits down in the cavity and has a rubber plug to keep water out….well over time, those plugs shrink and don’t do much.
So the technical service bulletin has you build a damn around the rear sensor plug area like this to help funnel and stray water around the sensor where it can exit the rear of the engine.
As you can see, the old knock sensor was definitely rusted and exposed to water.