Knock (Detonation) Sensor What is it? Knock (Detonation) Sensor What does it do? It picks up engine frequencies due to improper combustion and retards timing to the proper curve. Why does the original fail? Prolonged heat and vibration or over torquing during installation. What happens when it fails? The vehicle’s performance suffers. "Detonation" or "Pinging" engine knocks as well as improper timing control. The crystal breaks down and can no longer create the proper signal. What is special about it? It is installed in a location designated by the manufacturer for optimum sensing qualities to give maximum timing while prolonging engine life. When should it be replaced? Every 40,000 to 60,000 miles or failure. Where can I get this replaced? You do not need to go back to the dealer for this part. Professional technicians can service this system and install top quality Standard knock sensors for you when required. Back to Motorist FAQ Visit our Resource Library  for available downloads