P0325 Toyota 4Runner
Knock Sensor 1 Circuit Malfunction (Bank 1) · Powertrain Code · Medium
What is P0325?
The knock sensor 1 on bank 1 is not functioning properly. The ECM cannot detect engine knock/detonation.
When the Toyota 4Runner 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 Toyota 4Runner.
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 Toyota 4Runner.
Common Causes on Toyota 4Runner
- Knock sensor failed or cracked — Toyota knock sensors are piezoelectric and brittle
- Knock sensor wiring harness damaged by heat from exhaust manifold
- Knock sensor bolt torqued incorrectly — must be exactly 29 ft-lbs per Toyota spec
- Engine knock from carbon buildup or low-octane fuel triggering false readings
Symptoms
- Check Engine Light on
- ECM retards ignition timing as a precaution — reduced power and efficiency
- Slight pinging or knocking sound on acceleration may not be present
- Reduced fuel economy from retarded timing
Notes for Toyota 4Runner
On Toyota V6 engines (1GR-FE, 2GR-FE) the knock sensor is buried under the intake manifold — plan for 3-4 hours labor for replacement.