P2347 code meaning
Cylinder 12 Above Knock/Combustion Vibration Sensor Threshold
Powertrain system Generic code P23xx codes Check engine light
What P2347 means
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.
P2347 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 8 hours
- Clears after repairAfter a drive cycle
Symptoms of P2347
- Check engine light on
- Reduced power
- Possibly knocking under load
Common causes of P2347
- PossibleCarbon deposits in cylinder 12
- PossibleLow-octane or contaminated fuel
- Less likelyCylinder 12 running lean (restricted injector)
- Less likelyMechanical noise near the sensor of that bank
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Knock sensorKnock sensor wiringCylinder 12 combustion
What each part of P2347 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 3 | Area: ignition system or misfire. |
| 47 | The exact fault in that area. |
What to do next
- Note P2347 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2347
What does P2347 mean?
P2347 means "Cylinder 12 Above Knock/Combustion Vibration Sensor Threshold". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P2347?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P2347 fail an emissions test?
Yes, it can. P2347 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2347 to fix?
Difficulty: medium. A typical repair takes 0.5 to 8 hours of work. This is a job for a workshop.
Will P2347 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.