P0325 Honda Civic
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 Honda Civic 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 Honda Civic.
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 Honda Civic.
Common Causes on Honda Civic
- Failed knock sensor (heat-degraded over time)
- Corroded knock sensor wiring connector
- Loose knock sensor mounting bolt (must be torqued to spec)
- Engine block crack or coolant leak near knock sensor (rare)
Symptoms
- Check Engine Light on
- Reduced engine performance (PCM retards timing as precaution)
- Slightly lower fuel economy
- Engine may feel sluggish on acceleration
Notes for Honda Civic
Knock sensor replacement requires removing the intake manifold on most Honda 4-cylinder engines — budget 2-3 hours for the job.