P0325 Code – Meaning, Causes, Symptoms (& How To Fix)

If you're experiencing problems with your car and see the P0325 code, don't panic. This post will tell you everything you need to know about the code and how to fix it.

P0325 Code

When the Check Engine Light comes on your dashboard, it’s important to whip out your code scanner to see what’s going on. If you get the P0325 code, you can find the steps for a quick resolution right here.

Not only do we cover the meaning of the P0325 trouble code, but we show you what symptoms you may notice when it’s going on. We also cover the top causes, so you can figure out how to fix it.

Code P0325 Definition

P0325 – Knock Sensor Circuit Malfunction (Sensor 1, Bank 1)

What Does the P0325 Code Mean?

The P0325 DTC states that there’s a Knock Sensor Circuit Malfunction (Sensor 1, Bank 1). The Powertrain Control Module (PCM) detected a problem with the knock sensor or the circuit. Because it is set as Bank 1, it pertains to the sensor found on the same side of the motor as the #1 cylinder.

The engine’s knock sensor is meant to detect abnormal vibrations occurring because of trouble with the combustion. Most cars have one or two of these sensors. When the PCM sees that the signal is beyond the predetermined specs set by the manufacturer, this trouble code will be set. 

READ MORE: Bank 1 vs Bank 2 – Sensor 1 & 2 (Locate O2 Sensors)

P0325 Trouble Code Symptoms

The only certain symptom with the P0325 code is that the Check Engine Light will come on. Beyond that, it’s possible to notice a few other symptoms, mainly dealing with the drivability and performance of the vehicle.

Here are the top P0325 DTC symptoms.

Causes of the P0325 Code

Because this code has to do with the knock sensor, you are going to automatically assume that’s the part that has failed. While this might be the case, it’s important to walk through all of the diagnostic steps to be sure.

Here are a few of the top P0325 DTC causes.

  • Defective knock sensor
  • Damaged connection or malfunctioning wiring
  • Failing PCM (not as likely)

RELATED: 5 Symptoms of a Bad Knock Sensor (& Replacement Cost)

How Serious is the P0325 Code?

Low – For the most part, there’s no reason to run to the auto repair shop due to this code. You should be fine to drive your vehicle where you need to take it without worrying about other damage being done.

However, there could be a lack of power that causes some drivability concerns. Without the sensor working as it should, it also becomes more difficult to know if something goes wrong with the combustion process, so you don’t want to put off the repair if you can help it. 

What Repairs Can Fix the P0325 Code?

You don’t need to wonder how to fix the P0325 trouble code. With the proper diagnostic steps, it’s easy to pinpoint the exact problem, so you ensure the issue gets resolved the right way. Once you walk through the steps we have listed, you might find that one of these repairs is called for.

  • Replace knock sensor
  • Repair a damaged connection or malfunctioning wiring
  • Updates/replace PCM 

Common P0325 Diagnosis Mistakes

The P0325 trouble code seems like a clear-cut indication that the knock sensor is in bad shape. However, you can’t just make assumptions without taking the time to verify the problem.

If you overlook the inspection and diagnosis, you could miss something obvious. In the end, you could replace parts that aren’t needed, thereby wasting your time and money. 

How to Diagnose the P0325 Trouble Code

Even if you aren’t a professional mechanic, you can use your code scanner to get to the bottom of the P0325 code. Here are a few steps to consider trying, but you should also reference your car’s service manual for more instructions.

  1. Check the engine codes. Make a note of any other codes that occur.
  2. Clear out the codes and do a road test to see what comes back.
  3. With the live data function on your scanner, you can measure the voltage of the knock sensor to ensure it remains within the range set in your service manual.
  4. Look at the wiring and connectors of the knock sensor. This is especially important if you don’t get any signal from your previous step. If you notice any damaged or disconnected wires, repair this issue first to see if it gets rid of the code.
  5. If the code still persists, you want to try replacing the knock sensor and its harness.

If these steps haven’t resolved your issues, it’s best to visit your local auto repair shop. Beyond this, the PCM needs to be examined, which should only be done by professionals. 

Estimated P0325 Repair Cost

The diagnostic steps listed above should bring you to the appropriate repair. However, you still want to know what you are looking at spending. We estimate a few of the top repairs, along with the approximate labor and parts costs. 

  • Replace knock sensor – $275-$425
  • Repair damaged connection or malfunctioning wiring – $50-$450
  • Updates/replace PCM – $250-$2,500

Mechanics Tips about the P0325 Code

When dealing with the P0325 trouble code, the quality of your scan tool makes a big difference. While there are plenty of cheap scan tools that will get you the codes, many of them don’t have the additional features that help you with the diagnostics.

Instead, you should invest in a high-quality OBD-II scan tool to perform a more accurate diagnosis of this DTC. With the live data stream, you can get to the bottom of what’s going on much quicker than if you have the basic functions only. 

Magnus Sellén
Written by:

Magnus is the owner and main author of Mechanicbase. He has been working as a car mechanic for over 10 years, and the majority of them specialized in advanced car diagnostics and troubleshooting. Certified Automotive Diagnostic Technician.

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