Inspect wiring, connector routing, and grounds, then test the circuit to vehicle specifications. If the engine makes a real knocking sound, stop and have it checked.
Quick educational note
For information, not a diagnosis or repair instruction. Vehicle-specific checks are still required. Consult the manufacturer's guidance and a qualified technician.
How to use this information
This article explains general principles and does not establish what is wrong with your vehicle. Read the content limitations.