Generally, on most of these engines, the knock sensor(s) are located on the engine block, typically near the cylinder block, often on the passenger side (right side when facing the engine). They are usually small, threaded sensors.
To find it definitively:
1. Find your engine code: This is usually found on a sticker under the hood or in the driver's side doorjamb.
2. Use a repair manual specific to your engine: A repair manual (either a physical book or a digital version) for your specific year, make, model, and engine will show you the exact location of the knock sensor with a diagram. This is the most reliable method.
3. Search online with your engine code: Searching online with your specific engine code (e.g., "2004 Chevy Silverado 2500 5.3L knock sensor location") may yield images or forum discussions showing the location.
Caution: Working on your engine can be dangerous. If you are not comfortable performing this task, it's best to take your vehicle to a qualified mechanic.
