P0325 Subaru Forester
Knock Sensor 1 Circuit Malfunction (Bank 1) · Powertrain Code · Medium · Repair: Moderate
What is P0325?
The knock sensor 1 on bank 1 is not functioning properly. The ECM cannot detect engine knock/detonation.
When the Subaru Forester triggers code P0325 (knock sensor 1 circuit malfunction (bank 1)), it typically points to an issue in the powertrain system. Below you'll find the most common causes, symptoms, and repair options specific to the Subaru Forester.
This repair is rated moderate, meaning some experience and specialty tools required.
Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your Subaru Forester.
Common Causes on Subaru Forester
- Failed knock sensor on the boxer engine block
- Knock sensor wiring damage from road debris or heat
- Engine knock from low-octane fuel in turbo models
- Knock sensor corroded from exposure on the flat engine
Symptoms
- Check Engine Light on
- Reduced engine power (ECM retards timing)
- Worse fuel economy
- Sluggish acceleration
Notes for Subaru Forester
Subaru boxer knock sensors are more exposed to road debris than inline engines; inspect wiring during routine maintenance.