OBD-II Fault Code

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

Meaning, symptoms, likely causes, diagnostic checks and repair guidance for P0325.

System family

Powertrain

Generic/SAE

Repair category

Knock sensor / ignition control

Use this category to narrow your checks before replacing parts.

Severity

Medium

Severity is a general guide. Confirm with scan-tool data and vehicle symptoms.

What P0325 usually means

Knock Sensor 1 Circuit Malfunction (Bank 1 or Single Sensor).

Common symptoms

Check Engine light; Poor drivability or reduced fuel economy depending on fault

Likely causes

Faulty knock sensor; Wiring fault; Engine mechanical noise; Incorrect fuel octane

Diagnostic checks

Scan all modules and record freeze-frame data before clearing codes; Check battery voltage and related fuses; Inspect sensor wiring and mounting; Check for engine noise and correct fuel

Repair guidance

Repair wiring, replace sensor if confirmed, address mechanical noise/fuel issue

Verification after repair

Clear code, road-test through the same drive condition, then rescan

Note: Confirm vehicle make/model/year because manufacturer-specific codes can vary. A DTC identifies a circuit or system condition, not always the failed part.