P2339 covers cylinder 4. On a four-cylinder engine this is the last cylinder of the series, which is why Stellantis bulletin 09-009-26 lists exactly P2336 to P2339 for the 2.0L turbo PHEV (sales code ECX, Jeep Wrangler 4xe 2024–2025, Grand Cherokee 2023–2025): any of the four codes with the MIL on, often together with a knocking noise, qualifies for an engine replacement under an extended warranty because of machining debris and casting sand. In general the code means the knock control has seen vibration above the limit in the combustion window of cylinder 4 and retards that cylinder's spark. On six- and eight-cylinder engines the series continues with P2340; GM reports such cases as P0324, and Saab uses the sensor codes P0326/P0331 once more than one cylinder knocks.
Medium severity. Can I keep driving?You can drive in moderation without pushing the engine. If you hear knocking, avoid full-throttle acceleration.
Cylinder 4 is numbered according to the manufacturer: check your engine's manual before working on it.
Symptoms
- MIL on
- Knocking noise from the engine compartment
- Reduced power
Most likely causes
- Machining debris or casting sand damaging the engine (Stellantis bulletin 09-009-26)
- Low-octane fuel or high intake temperature
- Deposits raising compression in cylinder 4
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: hard
- It affects emissions.
What each character of P2339 means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- 3: Ignition and misfires
- 39: Specific fault in that system
Frequently asked questions
Can I keep driving with code P2339?
You can drive in moderation without pushing the engine. If you hear knocking, avoid full-throttle acceleration.
What causes code P2339?
The most common causes are: machining debris or casting sand damaging the engine (Stellantis bulletin 09-009-26); low-octane fuel or high intake temperature; deposits raising compression in cylinder 4.
Related codes
- P2336Cylinder 1 Above Knock/Combustion Vibration Sensor Threshold
- P2337Cylinder 2 Above Knock/Combustion Vibration Sensor Threshold
- P2338Cylinder 3 Above Knock/Combustion Vibration Sensor Threshold
- P2340Cylinder 5 Above Knock/Combustion Vibration Sensor Threshold
- P0324Knock/Combustion Vibration Control System Error
- P0331Knock/Combustion Vibration Sensor B Circuit Range/Performance
- P0304Cylinder 4 Misfire Detected
Sources
- static.nhtsa.gov: MC 11032844 0001
- 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.