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P2344 OBD-II Trouble Code: Cylinder #9 Above Knock Threshold

check engine light

P2344 code definition

This is the generic trouble code for Cylinder #9 Above Knock Threshold.

What the P2344 code means

When a vehicle sets this code it means that the PCM (powertrain control module) has received a voltage input reading from the cylinder 9 knock sensor circuit that is not within the expected parameters. The purpose of the knock sensor is to alert the PCM to any abnormal noises related to cylinder detonation. The sensor serves as a type of microphone, carefully monitoring the ping that a cylinder makes when it fires. Knock sensor circuits are typically made up of a five-volt signal wire.

What causes the P2344 code?

A number of conditions may cause a vehicle to store this DTC:

  • A faulty knock sensor
  • Damaged or corroded wires or connectors, or loose connections
  • Abnormal fuel to air ratio causing an anomaly in cylinder detonation
  • Other cylinder firing malfunctions

When a vehicle stores this code, it is often indicative of a more serious underlying problem. While the knock sensor itself may be faulty, the abnormal voltage signal could also be the result of an engine malfunction.

What are the symptoms of the P2344 code?

The Check Engine Light will illuminate, either staying on for long periods of time, staying on all the time, or coming on and going off intermittently. You may also notice sluggish acceleration, reduced power while driving, and spark knock. Spark knock is the result of fuel detonation rather than the expected smooth burn as a cylinder fires. It’s also known as pinging or engine knock.

How does a mechanic diagnose the P2344 code?

Diagnosing this DTC may require:

Common mistakes when diagnosing the P2344 code

One of the most common errors is to automatically replace the knock sensor, assuming it must be faulty, without also investigating other underlying causes of the problem. It could very well be that the sensor is performing its job of alerting the PCM of a serious issue.

How serious is the P2344 code?

This DTC should be addressed as soon as possible due to the potential for an engine malfunction which could compromise safety as well as the engine’s integrity if allowed to go unchecked.

What repairs can fix the P2344 code?

Repairs for this code may include:

Additional comments for consideration regarding the P2344 code

Experts highly recommend always addressing any DTCs that have stored prior to the current code. In the case of the cylinder #9 above knock threshold error, it is particularly crucial to diagnose and repair any other problems which are present at the same time. This is due to the fact that P2344 often sets when something else is causing the engine to produce detonation and make more noise than it should. When this happens, the engine adjusts its timing in order to protect itself – this can affect other components and change the way the engine functions.

Knock sensors may be situated in a way that makes them difficult to access for testing. If this is the case with your vehicle, the sensor may need to be diagnosed using a process of elimination. Once all other possible causes have been ruled out, it may be prudent to assume the sensor is faulty.

Need help with a P2344 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.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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