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P0324 OBD-II Trouble Code: Knock Control System Error

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P0324 code definition

When the PCM (powertrain control module) detects an incorrect voltage reading from the knock sensor circuit, it will record a P0324 code and illuminate the Check Engine Light.

What the P0324 code means

The knock control system monitors the engine’s cylinders and sends input signals to the PCM. The PCM uses this information to predict when a knock will occur and adjust the fuel delivery and ignition timing to the appropriate cylinder(s) to prevent knocks and misfires. When there is an error with the knock control system, the PCM cannot get the proper data to do this, and it can result in engine knocking, pinging, and/or misfiring problems.

What causes the P0324 code?

Some of the most common causes of a P0324 code include:

  • A defective knock sensor
  • A poor electrical connection to the knock sensor’s circuit
  • A bad, open, or shorted knock sensor harness
  • A faulty PCM (rare)

What are the symptoms of the P0324 code?

When the P0324 code is stored, you can expect some or all of these symptoms to occur:

  • Illuminated Check Engine Light
  • Decreased fuel efficiency
  • Rough idle
  • Lack or loss of acceleration

Oddly enough, if you notice no symptoms at all, it could be worse than if you experience all of these symptoms. Some vehicles have a safety feature in which the PCM creates a “safe point” that allows you to drive the vehicle home or to a service station without doing damage to the engine.

How does a mechanic diagnose the P0324 code?

When diagnosing a P0324 code, the mechanic will first test the system for any stored codes using an OBD-II scanner. Then they will do a visual inspection to look for any problems with the wiring, connectors, harness, or the rest of the knock control system. They’ll then either use an oscilloscope or a knock sensor tester to determine whether the knock sensor is bad or if something else is going on.

With each step they take to determine what the problem is and how to fix it, they will clear the code(s) and retest the system so that they know exactly which part of the system was the problem and how to fix it. After determining the most probable cause of the code and making the necessary repairs, they will test the system once more and take a test drive to determine if there may be an intermittent problem that needs to be addressed.

Common mistakes when diagnosing the P0324 code

Sometimes, especially if other codes were recorded before the P0324, there may not actually be anything wrong with the knock sensor system. In fact, it might just be doing its job, detecting knocks in the engine. Always proceed by fixing each code you see in the order it was recorded to avoid this kind of problem.

How serious is the P0324 code?

The knock sensor system is an important part of your engine and is essential to its functionality. Allowing a malfunctioning knock sensor to go unresolved is a good way to do permanent damage to your engine, potentially put yourself in a dangerous driving situation, and/or incur some much more expensive repairs down the line.

What repairs can fix the P0324 code?

Depending on what’s causing the PCM to store the P0324 code, the solution could be:

  • Addressing a knocking, pinging, or misfiring engine issue
  • Replacing the knock sensor
  • Repairing a poor electrical connection to the knock sensor’s circuit
  • Replacing the wiring harness for the knock sensor
  • Replacing or reprogramming the PCM (rare)

Additional comments for consideration regarding the P0324 code

Even if a malfunctioning knock sensor system isn’t doing damage to your engine, if this code is stored in the PCM, your vehicle will not be able to pass an OBD-II emissions test. To avoid further repairs later on and get your vehicle ready to pass an emissions test for registration, go ahead and get this problem resolved now.

Need help with a P0324 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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