P2343
Cylinder 8 Above Knock Threshold
Sustained knock above the threshold on cylinder 8 — typical on V8 engines under load with poor fuel.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Low octane or contaminated fuelCommon
- Carbon deposits raise compression locallyPossible
Parts involved
- Knock Sensor
- Cylinder 8
P2343 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.