CarSense › Trouble codes › P0325

P0325: Knock Sensor 1 Circuit Malfunction (Bank 1 or Single Sensor)

What this check-engine code means in plain English, what usually causes it, and what a fix typically costs.

Severity: Monitor — not an emergency, but don't ignore it

What P0325 means

The knock sensor detects engine vibrations caused by abnormal combustion (knocking or pinging). When the powertrain control module (PCM) detects a problem with the knock sensor circuit on Bank 1, it sets this code. Without a functioning knock sensor, the engine cannot adjust timing to prevent damaging detonation.

What causes P0325?

Likely
Faulty knock sensorThe sensor itself has failed internally or its piezoelectric element has degraded over time and heat cycles.
Likely
Damaged wiring or connectorCorroded, broken, or shorted wiring between the knock sensor and PCM disrupts the signal.
Possible
Loose knock sensor mountingAn improperly torqued or loose sensor cannot accurately detect engine vibrations.
Less common
PCM issueThe engine computer itself may have a fault in the knock sensor input circuit, though this is rare.

Is P0325 safe to drive?

Drive it?
Usually yes, short-term
Watch for
Reduced fuel economy, pinging sounds, or hesitation under load
DIY-friendly?
Moderate; sensor replacement is straightforward but access can be difficult on some engines.

You can typically drive short-term with this code, but the engine may run less efficiently and use more fuel. Without knock sensor feedback, the PCM cannot protect the engine from damaging detonation under heavy load or with low-quality fuel, so avoid aggressive driving and get it diagnosed soon.

P0325 repair cost

~$150 – $400+

Industry-average estimates. Cost depends mainly on sensor location and labor access; some engines require removing intake components to reach the sensor.

Which one is it for your car?

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