Cylinder 5 is located in the middle of V6 or V8 engine blocks. When the knock sensor registers detonation in cylinder 5, the computer delays ignition timing to protect the engine. If the knock continues, it sets this code. Bad fuel injectors, worn spark plugs, or vacuum leaks on the cylinder 5 intake runner are common causes.
Mechanic Glossary
5 Above Knock Threshold
A fault indicating that combustion vibrations in cylinder 5 exceed safe limits.
Frequently Asked Questions
The engine computer detected pre-ignition knocking in cylinder 5 that exceeded the safe operating noise limit.
Carbon buildup on the piston, a lean air-fuel ratio in cylinder 5, a bad spark plug, or low-octane fuel.
Swap the spark plug and coil pack, run a carbon clean, or inspect the fuel injector for blockages.