P0327 Knock Sensor Fault Diagnosis and Fix for 2001 Chevrolet Silverado 5.3L V8

Check for wiring issues connecting to the knock sensor. A simple test involves lightly tapping the exhaust manifold while the engine is running; if RPM fluctuates, the sensor is likely functioning properly.

I performed the exhaust tap test on both sides of the manifold with a small hammer and observed no change in engine RPM. This suggests either a faulty sensor or an issue with signal transmission. I'm unsure exactly where the knock sensor is located—some sources indicate it's positioned behind the exhaust manifold, directly behind or to the rear of the engine. With so many sensors present, identifying the correct one can be challenging.

Consider obtaining a printed diagnostic reference from auto parts stores like AutoZone or through manuals such as Chilton's or Haynes. These resources often provide detailed diagrams and troubleshooting steps for specific vehicle models. I don't have access to one myself, but they can be very helpful. Good luck—please update if you find a solution!

I purchased a Chilton's manual and discovered that the 2001 Silverado 5.3L actually has two knock sensors, both located underneath the intake manifold. After disassembling the intake, I found them severely clogged with water and mud due to leaking seals—a known issue on this model. I cleaned out the debris and replaced both sensors. I applied RTV silicone to reseal the mounting areas before reassembly. The check engine light has not returned, indicating that the problem may now be resolved. Thanks for the helpful input!

Interestingly, some Chrysler vehicles also place knock sensors under the intake manifold—this design appears to have been adopted in certain models. It's a valuable lesson: knowledge grows with experience! Congratulations on solving it and thanks for sharing your success story!

Hi everyone—I replaced the knock sensors three times, first two sets purchased from eBay at low cost. I initially thought they were defective, so I bought higher-quality ones. Still receiving P0327. I tightened the sensor mounting to 15 ft-lbs, sealed the top with RTV silicone (no thread sealant used). I measured resistance and got around 100 ohms—within expected range—but I'm not detecting 5 volts at the sensor terminals. Does this indicate a potential PCM issue? Any guidance would be much appreciated.

Arthurrig — please consider starting a new post with your full vehicle details: year, make, model, engine type, and all active diagnostic codes. Also include any recent repairs or modifications you've made so the community can better assist.