OBD-II code · Powertrain (generic, extended)
P2344 Cylinder 9 Above Knock/Combustion Vibration Sensor Threshold
The knock or combustion-vibration sensor monitors the structure-borne noise of each cylinder. The signal level for cylinder 9 has stayed above the diagnostic threshold for an extended period, indicating either persistent knock or an electrical fault that biases the channel high.
Is it safe to drive with P2344?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyPersistent knocking on cylinder 9 (low-octane fuel, carbon deposits, hot spot)
- PossibleSensor or wiring biased high by short or moisture
- Less likelyMechanical knock from bearings, piston pin or wrong torque
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.8–4 h
- Emissions test
- Likely to fail
- Parts involved
- Knock Sensor, Knock Sensor Wiring, Fuel Octane Quality, Cylinder 9 Combustion
Related codes
- P2345Cylinder 10 Above Knock/Combustion Vibration Sensor Threshold
- P2346Cylinder 11 Above Knock/Combustion Vibration Sensor Threshold
- P2347Cylinder 12 Above Knock/Combustion Vibration Sensor Threshold
- P2341Cylinder 6 Above Knock Threshold
- P2342Cylinder 7 Above Knock Threshold
- P2343Cylinder 8 Above Knock Threshold
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.