Review on 🔥 213-3521 ACDelco GM Original Equipment Ignition Knock (Detonation) Sensor by Richard Miller

These sensors are VERY sensitive to shock. Since the people who deliver this product to your door usually throw around boxes, there is a good chance that it will be damaged. Before installation, measure the resistance with a multimeter! I had to do this job twice because I didn't test the new part. I installed 2 new knock sensors in my 2001 Silverado 5.3 after receiving code P0332. I also installed a new wiring harness, cleaned everything, RTV sealed the spark plugs, etc. A few days later my code P0332 came back. After some research I found out that the sensors should measure around 99k ohms. This is measured between the body of the sensor itself and the single pin connector in the middle. One of mine measured 10k ohms. So I have to do all the work twice! Only this time it was even harder as I had to scrape and scrape a fresh RTV. I measured the replacement sensor prior to installation, 99k ohms per point. I think Delco's AC sensors are good quality, but like any knock sensor, you can't drop it or hit anything. So measure it when you receive it!