P2339 OBD-II Trouble Code: Cylinder #4 Above Knock Threshold

Our certified mechanics come to you · Get a fair and transparent estimate upfront

Red-stars EXCELLENT RATING ON

Cost of diagnosing the P2339 code

P2339 is a diagnostic trouble code (DTC) for "Cylinder #4 Above Knock Threshold". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford$20.00
Toyota$20.00
BMW$20.00
SCHEDULE P2339 DIAGNOSTIC Get a fair and transparent estimate upfront

P2339 code definition

The P2339 trouble code indicates that a voltage level read from the knock sensor for engine cylinder 4 has been reported falling over the voltage limits outlined by the manufacturer.

What the P2339 code means

An engine's knock sensor detects vibrations caused by the engine being physically knocked. This will affect the It may be found on the engine block, intake manifold or the engine cylinder head. The knock sensor will record physical disturbances by varying voltage levels and feed the data into the vehicle's Powertrain Control Module (PCM). A P2339 will be registered in the vehicle's computer if the knock sensor detects an abnormally high amount of shock to engine cylinder 4.

What causes the P2339 code?

Although a faulty knock sensor is sometimes the case for a P2339 trouble code, if the sensor received a higher-than-normal voltage, a real engine problem is likely. The exact cause of the engine trouble should be evident by the other trouble codes that come alongside the P2339. The P2339 can also be the result of wiring concerns; broken, faulty or corroded wiring or connectors can ruin the knock sensor's electrical circuit, thereby feeding an inaccurate voltage input signal to the PCM.

What are the symptoms of the P2339 code?

In the case of a P2339 code, the engine may suffer from a general lack of power and experience problems with acceleration. The P2339 can be identified easily with the trouble code on the vehicle computer, as well as the illuminated dashboard trouble lamp. These symptoms are for purely diagnostic purposes only. In addition, because a P2339 indicates a potential malfunction in an engine-related sensor, the service engine lamp on the dashboard may act erratically until the issue is fixed.

How does a mechanic diagnose the P2339 code?

The P2339 code may be first identified by using an OBD-II code reader to scan the code. If there aren't any discernable issues with the engine itself, it is reasonable to suspect a faulty sensor. However, in the majority of cases, the P2339 code will come alongside other trouble codes relating to the engine. These other engine-based codes should be addressed before looking at the knock sensor. If all other engine issues are fixed, the P2339 should go away on its own. Nonetheless, all electrical wiring related to the knock sensor should be inspected for potential issues, including corrosion, disconnection and general damage.

Common mistakes when diagnosing the P2339 code

When a P2339 trouble code is reported, the engine's knock sensor is sometimes mistakenly reported as faulty. If the knock sensor has reported an issue, it is quite possible that the issue is real. Faulty knock sensors are known to occur, by replacing a sensor mistakenly will waste resources without doing anything to solve the root problem.

How serious is the P2339 code?

Due to the fact that the knock sensor is used to report potentially serious issues with the engine, a knock sensor code is most often a subsequent effect of an engine problem. Although the P2339 code is known to cause acceleration issues on its own, its accompanying trouble codes are usually what define its severity as an issue.

What repairs can fix the P2339 code?

  • Other trouble codes relating to the engine's performance should be solved before dealing with the knock sensor, provided others have been reported.

  • If there is nothing else wrong with the vehicle's engine system, suspect a faulty knock sensor. If the knock sensor is faulty, replace it as needed.

  • Replace any other engine-related components you have identified as being worn out or faulty. Any disconnected, broken or otherwise faulty electrical wiring should be replaced.

  • Once you have completed your repairs to the vehicle, give it a test drive. This will let you know whether the problem has been solved permanently or not. Recheck the computer afterwards to see if the code has returned or not.

Additional comments for consideration regarding the P2339 code

Some models and manufacturers will require the vehicle report the issue over the course of multiple drive cycles before the trouble code is officially logged.

Need help with a P2339 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701- 6230.

trouble codes
P2339
Check Engine Light

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P2339 code.

SCHEDULE P2339 DIAGNOSTIC
Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.8/5

Number of Reviews

5,626

Rating Summary
5,199
206
50
34
137
5,199
206
50
34
137

Robert

11 years of experience
104 reviews
Robert
11 years of experience
Nissan Quest - Check Engine Light is on - Alexandria, Virginia
Punctual. Knowledgeable. Professional. Empathic, went the extra mile to explain in lay words the mechanical jargon. Excellent manners and customer service oriented. Client’s best interest and safety was always his top priority. From now on your company has in me a client for life. Thanks Robert!!!! 

Chris

21 years of experience
1861 reviews
Chris
21 years of experience
Mercedes-Benz E320 - Check Engine Light is on - Ladera Ranch, California
Chris was friendly, professional and knowledgeable. He got to the point of my concerns, explained what he was finding on his system and gave me his recommendations. I fully appreciate him taking the time to explain everything and a bit of history on my vehicle. Thanks again Chris.

Michael

15 years of experience
574 reviews
Michael
15 years of experience
Hyundai Accent - Check Engine Light is on - Marietta, Georgia
I had a great experience with Michael. He's extremely professional, friendly, and understands his craft. Highly recommended.

Chris

15 years of experience
274 reviews
Chris
15 years of experience
Dodge Durango - Check Engine Light is on - San Diego, California
Showed up early, was a friendly dude, kept me informed via text, did clean work and finished early. Would hire again.


More related articles

P0212 OBD-II Trouble Code: Injector Circuit Malfunction - Cylinder 12
P0212 P0212 code definition Injector Circuit Malfunction - Cylinder 12 What the P212 code means P0212 is telling us the Engine Control Module (ECM) has detected a fault within the cylinder 12 fuel injector circuit. This code is specifically...
P2287 OBD-II Trouble Code: Injector Control Press Sensor Circuit Intermittent
P2287 P2287 code definition Injector Control Press Sensor Circuit Intermittent What the P2287 code means P2287 is an OBD-II generic code for the engine control module (ECM) detecting that the injector control pressure (ICP) sensor is intermittently not registering a...
P003A OBD-II Trouble Code: Turbocharger/Supercharger Boost Control "A" Position Exceeded Learning Limit
The P003A trouble code means the Electronic Computer Module (ECM) has detected an issue in the turbocharger or supercharger system.

Related questions

Reduced Engine Power message

The "Reduced Engine Power" message is the computer going into failure mode. This mode is to protect you from a possible problem of the throttle getting too high. The mode happens when one of the engine sensors is having a...

Getting Red Lighting Bolt Warning Light and Check Engine Light

Hi there. Assuming the Check Engine Light and red lightning bolt were on before your vehicle experienced the no start condition. This would indicate a malfunction in the electronic throttle control system. The computer has recognized the fault and stored...

Accelerater is not working.

The most common causes of Diagnostic Trouble Code P2118 are failure of the throttle actuator control motor, a failed pedal position sensor, a faulty throttle position sensor, an open or short in the actuator circuit, or a poor electrical connection...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com