P0325 Code: Knock Sensor 1 Circuit Malfunction (Bank 1)

🟠 Moderate severity · drivable

Drivable, but the computer may reduce performance (retard timing) to protect the engine, so fix it soon.

What P0325 means

The knock sensor on bank 1 isn't sending a proper signal. This sensor detects engine knock (pinging) so the computer can adjust ignition timing to prevent damage; without it, the computer can't protect the engine from knock.

Symptoms

Check engine light is on
Reduced power or acceleration
Possible engine pinging or knocking
Poor fuel economy

Common causes

most common: Faulty knock sensor
common: Damaged wiring or loose connector at the sensor
less common: Engine mechanical noise confusing the sensor

How to fix it

Fix	DIY?	Typical cost
Inspect and clean the knock sensor connector	Yes	$0–10
Replace the knock sensor	Yes	$50–200
Repair damaged knock sensor wiring	Mechanic	$50–200

Frequently asked questions

Can I drive with a P0325 code?

Yes, but the engine can't protect itself from knock, and you may notice reduced power. Fix it soon.

What is the most common cause of P0325?

A faulty knock sensor. It's usually inexpensive and not too hard to reach.

How much does it cost to fix a P0325?

Typically $50–$200 for a new knock sensor.

Related codes

P0327

P0327 Code: Knock Sensor 1 Circuit Low Input (Bank 1)

P0328

P0328 Code: Knock Sensor 1 Circuit High Input (Bank 1)

P0330

P0330 Code: Knock Sensor 2 Circuit Malfunction (Bank 2)

P0325 by vehicle brand

Causes and repair costs for P0325 differ between makes. Pick your brand for the specifics.

P0325 on a Mercedes-Benz

Volkswagen

P0325 on a Volkswagen

Updated 2026-08. This page is informational and not a substitute for professional diagnosis.