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P0325 Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.


This code shows that there is a malfunction with the sensor one, bank one knock sensor. The purpose of knock sensors is to sense where there is air and fuel exploding in the engine.

This can cause a loss of power and damage to the vehicle over a long period of time. The code tells you that the knock sensor is not operating properly.


This diagnostic trouble code is a general OBD-II code that is associated with the knock sensor circuit. There is a possibility for this code to be seen in combination with other lean condition codes and knock sensor codes.

This code means that there is a malfunction within sensor one, bank one of the knock sensor circuit. The malfunction will be detected by the ECU when it is not receiving the correct signal from the knock sensor. This will cause the check engine light to illuminate on the dashboard.


There are several causes of the P0325 DTC code including failure of the ECU or the knock sensor. Another possible cause of this code is that there are issues with electrical connections or shorts in the wiring harness.

An engine that is running excessively lean and a fault in the engine coolant system are also potential causes.


An illuminated check engine light on the dashboard is the most common symptom of a P0325 DTC code. Another possible symptom is that the engine may have a lack of power that may be difficult to notice. In several cases, there have been no symptoms that indicate the code, and the drivability of the vehicle is typically unaffected.

The presence of the check engine light can cause you to fail an emissions test, so it is best to deal with the problem before this is required.


The first step that you should take when you are attempting to diagnose a malfunction is to research the Technical Service Bulletins to figure out if you are experiencing a known issue. If the symptoms match these common issues, they could be the causes of the symptoms.

There is a specific list of steps that a mechanic will take to diagnose P0325 DTC code. They will start by using a scan tool to check for codes and their history, as well as any pending and current codes.

They will then search for freeze frame data for each of these codes to see the conditions that the vehicle was under when the code was set. This can include the temperature of the coolant, engine RPM, the speed of the vehicle and run time. These codes will be cleared in order to have a fresh diagnosis. A road test will be performed with the goal of getting the check engine light to illuminate to confirm that the issue is present. While the engine is revving, a scan tool will be used to check if the knock sensor is operating properly. If it is operating properly, the resistance of the knock sensor will be tested. The diagnosis will be finished by testing the ECU following any of the manufacturer’s procedures if necessary.

Common mistakes

As with any code, simple mistakes can be made if all of the diagnostic steps are not completed in the correct order. There are times when the coolant system is the actual issue, and replacing the knock sensor will not immediately turn off the check engine light.

How serious is this?

P0325 DTC is generally not a serious code, and the vehicle should be able to be driven to a safe location when the malfunction happens. There are some vehicles that will experience a slight lack of power in the engine, because the ECU will slow down timing to prevent engine damage.

What repairs can fix the code?

There are a few repairs for P0325 that can easily be performed. You may need to replace the wiring harness, ECU or the knock sensor that is faulty. There also may be an electrical connection that needs to be repaired.

Related codes

None listed.


What happens when a knock sensor goes bad?

While driving on the highway, a bad knock sensor may also prevent the engine from accelerating properly and result in loss of fuel mileage. You might lose power when your vehicle’s computer detects a malfunctioning knock sensor.

Can a bad knock sensor damage the engine?

Yes. It is common for a bad know sensor to cause severe damage to the engine, which can cause a costly repair or engine replacement.


P0325 DTC is a code that is easy to repair, but it can be difficult to notice any symptoms. Fortunately, this code will not cause serious damage to your car right away, but it can cause damage to the engine if left untreated.

If you suspect that you are experiencing issues with this code, hiring a mechanic is usually the best choice. They will know how to properly follow each step of the diagnostic procedure and are equipped with all of the tools for testing.

P0325 Code – What Does It Mean & How To Fix It