P2338Cylinder 3 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
- P2338 sets when the knock signal assigned to cylinder 3 rises above its threshold. Because one or two knock sensors serve several cylinders, the module relies on the crank-angle window to tell which cylinder knocked; a code for just one cylinder therefore suggests something local: carbon build-up, a hot spot, a lean-running injector, a wrong spark plug, or mechanical noise that happens to fall into that window. Low-octane fuel tends to raise knock on every cylinder. Stellantis names P2338 with P2336, P2337 and P2339 in bulletin 09-009-26, which covers the 2.0L PHEV engine in Wrangler 4xe and Grand Cherokee 4xe models from Jeep, where foundry sand and machining chips are the cause and the engine is exchanged. Persistent knock can hole or melt pistons, so it should not be ignored.
- What you may notice
- Check engine light on
- Pinging under acceleration
- Noticeably less power
- Likely causes
- PossibleCarbon build-up or a hot spot in cylinder 3
- PossibleInjector of cylinder 3 delivering too little (lean, hot combustion)
- PossibleEngine damage from casting sand or chips (Stellantis 2.0L PHEV)
- RareKnock sensor loose or wrongly torqued, picking up noise
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €0 – €8,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.