P2347 ends the per-cylinder knock series that starts with P2336 for cylinder 1; it is the code for cylinder 12 and thus appears only on V12 engines such as those from BMW, Mercedes-Benz, Ferrari or Lamborghini. The engine module has found that the vibration in cylinder 12's combustion window exceeds the threshold and is holding back that cylinder's spark. The J2012 title speaks of a knock or combustion vibration sensor, so the series is not tied to a particular sensor type. No manufacturer was found that documents P2347 publicly; the only bulletin seen for the series, from Stellantis, covers cylinders 1 to 4 of a four-cylinder engine, and GM and Saab use P0324. Work through fuel, deposits, plug and injector of cylinder 12 and check for mechanical noise.
Medium severity. Can I keep driving?You can drive in moderation without pushing the engine. If you hear knocking, avoid full-throttle acceleration.
Cylinder 12 is numbered according to the manufacturer: check your engine's manual before working on it.
Symptoms
- Check engine light on
- Reduced power
- Possibly knocking under load
Most likely causes
- Carbon deposits in cylinder 12
- Low-octane or contaminated fuel
- Cylinder 12 running lean (restricted injector)
- Mechanical noise near the sensor of that bank
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 P2347 means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- 3: Ignition and misfires
- 47: Specific fault in that system
Frequently asked questions
Can I keep driving with code P2347?
You can drive in moderation without pushing the engine. If you hear knocking, avoid full-throttle acceleration.
What causes code P2347?
The most common causes are: carbon deposits in cylinder 12; low-octane or contaminated fuel; cylinder 12 running lean (restricted injector).
Related codes
- P2346Cylinder 11 Above Knock/Combustion Vibration Sensor Threshold
- P2345Cylinder 10 Above Knock/Combustion Vibration Sensor Threshold
- P2336Cylinder 1 Above Knock/Combustion Vibration Sensor Threshold
- P0324Knock/Combustion Vibration Control System Error
- P0330Knock/Combustion Vibration Sensor B Circuit
- P0312Cylinder 12 Misfire Detected
Sources
- en.wikipedia.org: V12 engine
- 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.