AutoCodesSubaru – P0325 Subaru

P0325 Subaru Code - Knock Sensor Circuit Malfunction

Quick Answer

A knocking vibration from the cylinder block is sensed as vibrational pressure by the Knock Sensor. Common causes include Faulty Knock Sensor, Knock Sensor circuit poor electrical connection, Knock Sensor harness is open or shorted. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means
P0325 Subaru indicates Knock Sensor Circuit Malfunction.
Common causes
Common causes include Faulty Knock Sensor, Knock Sensor circuit poor electrical connection, Knock Sensor harness is open or shorted.
Severity
Moderate - service should be scheduled soon.
Can I drive?
The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.
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Code Popularity 8,946
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Aug 15, 2020
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Code P0325 Subaru Description

A knocking vibration from the cylinder block is sensed as vibrational pressure by the Knock Sensor. This pressure is converted into a voltage signal and sent to the Engine Control Module (ECM). The ECM uses this signal to retard the ignition timing and protect the engine from this damaging pre-ignition.
Engine knock occurs within a specific frequency range. The Knock Sensor, located in the engine block, cylinder head, or intake manifold, is tuned to detect that frequency.
Inside the knock sensor is a piezoelectric element. Piezoelectric elements generate a voltage when pressure or vibration is applied to them. The piezoelectric element in the Knock Sensor is tuned to the engine knock frequency.
The vibration from the engine knocking vibrates the piezoelectric element generating a voltage. The voltage output from the Knock Sensor is highest at this time.
OBDII Code P0325 Subaru - Knock Sensor Circuit Malfunction - AutoCodes.com
P0325 Subaru Code - Knock Sensor Circuit Malfunction

What are the Possible Causes of the DTC P0325 Subaru?

  • Faulty Knock Sensor
  • Knock Sensor circuit poor electrical connection
  • Knock Sensor harness is open or shorted
  • Faulty Engine Control Module (ECM)

How to Fix the DTC P0325 Subaru?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

Code Tech Notes

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0325 Subaru code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0325 Subaru code?

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0325 Subaru Code

1. What are the common symptoms of the P0325 OBDII code on a Subaru related to a knock sensor circuit malfunction?

- Common symptoms include poor engine performance, engine knocking or pinging noises, reduced fuel efficiency, and in some cases, the Check Engine light illuminating on the dashboard.

2. What are the main causes of the P0325 OBDII code indicating a knock sensor circuit malfunction in a Subaru?

- The primary causes can be a faulty knock sensor, damaged wiring or connectors in the knock sensor circuit, or issues with the engine control module (ECM).

3. How can I diagnose the P0325 OBDII code on my Subaru related to a knock sensor circuit malfunction?

- Diagnosing this code usually involves checking the knock sensor and its wiring for any visible damage, testing the sensor's resistance, and using a scan tool to monitor the sensor's readings.

4. What are some repair tips for fixing the P0325 OBDII code caused by a knock sensor circuit malfunction in a Subaru?

- Repair tips include inspecting and repairing any damaged wiring or connectors, replacing the knock sensor if faulty, and clearing the code with a scan tool after completing the repairs.

5. Can driving with the P0325 OBDII code indicating a knock sensor circuit malfunction in a Subaru cause further damage to the vehicle?

- Continuing to drive with this code may lead to decreased engine performance, potential damage to the engine due to pre-ignition, and reduced fuel efficiency over time.

6. How much does it typically cost to repair the P0325 OBDII code related to a knock sensor circuit malfunction on a Subaru?

- The cost of repair can vary depending on the exact cause of the issue, but it may range from $150 to $400 for parts and labor.

7. Are there any preventive measures to avoid the P0325 OBDII code appearing in a Subaru due to a knock sensor circuit malfunction?

- Regularly inspecting and maintaining the knock sensor and its wiring, avoiding harsh driving conditions, and promptly addressing any engine performance issues can help prevent this code from occurring.

8. Can a DIY enthusiast with basic automotive knowledge fix the P0325 OBDII code caused by a knock sensor circuit malfunction in a Subaru?

- While some DIYers may be able to address this issue themselves by following repair guides and using the necessary tools, it is recommended to consult a professional mechanic for accurate diagnosis and repair.

9. How long does it usually take to repair the P0325 OBDII code related to a knock sensor circuit malfunction on a Subaru?

- The repair time can vary depending on the extent of the issue and the availability of parts, but it typically takes around 1 to 2 hours for a skilled mechanic to diagnose and fix the problem.

10. Will resetting the Check Engine light after repairing the P0325 OBDII code on a Subaru related to a knock sensor circuit malfunction prevent the code from reappearing?

- Resetting the light only clears the code from the system, but if the underlying issue causing the code is not properly addressed, it may reappear. It is crucial to ensure the root cause is fixed to prevent future occurrences.

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