Cylinder 5 Above Knock Threshold
The knock-sensor evaluation reports cylinder 5 above the knock threshold over a sustained window. The ECU retards ignition for that cylinder; persistent knock indicates poor fuel quality, carbon deposits or cooling issues.
Affected components
- Knock sensor
- Cylinder 5
Common causes
- High likelihood: Low octane or contaminated fuel
- Medium likelihood: Carbon deposits raise compression locally
- Low likelihood: Local cooling issue at cylinder 5
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
- A drive cycle may be required after repair
Related codes
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.