P2340Cylinder 5 Above Knock/Combustion Vibration Sensor Threshold
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2340 reports knock above threshold for cylinder 5, so it can only occur on engines with at least five cylinders – inline-five, six-cylinder, V8 or larger. The principle matches the rest of the series: the module evaluates the knock sensor signal in the crank-angle window of each combustion and retards spark individually when one cylinder knocks. No manufacturer was found that documents P2340 publicly; the Stellantis bulletin for P2336–P2339 concerns a four-cylinder engine and therefore stops at cylinder 4. GM and Saab detect the same condition but store P0324 (excessive knock on a single cylinder for more than 8 s). Causes are usually local to cylinder 5: deposits, a lean injector, a wrong plug or internal damage; poor fuel would affect several cylinders.
- What you may notice
- Check engine light on
- Pinging or knocking under load
- Less power, higher consumption
- Likely causes
- PossibleCarbon deposits or glowing particles in cylinder 5
- PossibleInjector of cylinder 5 delivering too little
- RareWrong heat range or damaged spark plug
- RareMechanical damage in cylinder 5 (piston, valve)
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €0 – €4,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.