OBD-II code · Powertrain (generic, extended)
P2343 Cylinder 8 Above Knock Threshold
Sustained knock above the threshold on cylinder 8 — typical on V8 engines under load with poor fuel.
Is it safe to drive with P2343?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyLow octane or contaminated fuel
- PossibleCarbon deposits raise compression locally
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–4 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Knock Sensor, Cylinder 8
Related codes
- P2336Cylinder 1 Above Knock Threshold
- P2337Cylinder 2 Above Knock Threshold
- P2338Cylinder 3 Above Knock Threshold
- P2339Cylinder 4 Above Knock Threshold
- P2340Cylinder 5 Above Knock Threshold
- P2341Cylinder 6 Above Knock Threshold
- P2342Cylinder 7 Above Knock Threshold
- P2344Cylinder 9 Above Knock/Combustion Vibration Sensor Threshold
- P2345Cylinder 10 Above Knock/Combustion Vibration Sensor Threshold
- P2346Cylinder 11 Above Knock/Combustion Vibration Sensor Threshold
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.