Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Considering you already replaced the knock sensors and the computer it sounds like the problem is the wiring harness itself. Water gets down in that area and can corrode the connectors. When replacing the connectors put silicone around them to keep water out in the future. Let me know if you have questions, thanks.
P0332 Knock Sensor Circuit Low Frequency (Bank 2)
At this point you will need to do a resistance test between knock sensors and pcm and knock sensos and ground, maybe clean the knock sensor mounting surface or replace wire between sensor and pcm. Here is a wire diagram, let me know if you have questions, thanks.