P2343 belongs to cylinder 8, the last cylinder of a V8, and is stored when the knock intensity measured in that cylinder's crank-angle window stays above the calibrated limit. The knock control first answers with spark retard for cylinder 8 alone, and on turbocharged engines it may also lower boost; the code marks that this cylinder keeps knocking. Prolonged detonation can melt or hole a piston or crack the head, so the cause matters more than the light. Typical checks are fuel grade, carbon in cylinder 8, plug type and gap, injector delivery and, if the noise is mechanical, the parts near that bank's sensor. No manufacturer publishes P2343 in openly available documents; GM and Saab cover the same case with P0324 (one cylinder knocking for over 8 s).
Medium severity. Can I keep driving?You can drive in moderation without pushing the engine. If you hear knocking, avoid full-throttle acceleration.
Cylinder 8 is numbered according to the manufacturer: check your engine's manual before working on it.
Symptoms
- Check engine light on
- Pinging or knocking, mostly under load
- Reduced power, possibly less boost on turbo engines
Most likely causes
- Carbon build-up in cylinder 8
- Fuel grade below the requirement
- Wrong plug type or gap in cylinder 8
- Cylinder 8 running lean from low injector delivery
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It affects emissions.
What each character of P2343 means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- 3: Ignition and misfires
- 43: Specific fault in that system
Frequently asked questions
Can I keep driving with code P2343?
You can drive in moderation without pushing the engine. If you hear knocking, avoid full-throttle acceleration.
What causes code P2343?
The most common causes are: carbon build-up in cylinder 8; fuel grade below the requirement; wrong plug type or gap in cylinder 8.
Related codes
- P2342Cylinder 7 Above Knock/Combustion Vibration Sensor Threshold
- P2341Cylinder 6 Above Knock/Combustion Vibration Sensor Threshold
- P2344Cylinder 9 Above Knock/Combustion Vibration Sensor Threshold
- P0324Knock/Combustion Vibration Control System Error
- P0332Knock/Combustion Vibration Sensor B Circuit Low
- P0308Cylinder 8 Misfire Detected
Sources
- saabwisonline.com: dtc p0324 p0326 p0331 p06b6 or p06b7
- en.wikipedia.org: Engine knocking
- law.cornell.edu: 13 CCR 1968.2
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.