P0325 means Knock Sensor 1 Circuit (Bank 1 or Single Sensor). There is a problem in the circuit for knock sensor 1, the sensor that listens for detonation so the computer can retard timing. It is a generic OBD-II code, so the definition is the same on any make, but the most likely cause varies by engine; confirm with a scan tool and the service information for your vehicle before buying parts.
What P0325 means
The engine computer uses the crankshaft position sensor to know engine speed and piston position, and the camshaft sensors to know which stroke each cylinder is on. On engines with variable valve timing, oil-driven cam phasers rotate the camshafts relative to the crankshaft under the control of solenoids. Timing codes come from a sensor that cannot be read, or from a measured cam angle that does not match the commanded one, so oil level and condition, sensor signals and mechanical timing all need checking.
P0325 symptoms
- Check engine light
- Reduced power or fuel economy as the computer pulls timing as a precaution
- Pinging under load on some vehicles
Common causes of P0325
- Damaged knock sensor wiring or connector
- Failed knock sensor
- Corrosion at the connector
How to diagnose P0325
- Inspect wiring and the connector
- Check sensor resistance or output as specified
- Make sure the sensor is torqued correctly, since mounting affects its signal
Can you drive with P0325?
Usually yes, but use the recommended fuel and avoid heavy load until repaired, because detonation protection may be limited.
P0325 tips
Knock sensors sit under the intake manifold on many V engines, so replacement can be a big job; check the connector and harness first, since heat and rodents damage them. Torque a new sensor exactly to specification, because over- or under-tightening changes its sensitivity.
Will P0325 clear itself?
If the fault stops, the computer turns off the check engine light by itself after several drive cycles without seeing it again, and the code stays in memory as history for a while. Clearing P0325 with a scan tool after a repair is fine, but if the cause is still there the code returns, sometimes within one drive. Disconnecting the battery also clears codes on most vehicles, but it erases learned fuel trims and idle settings as well.
Related codes
| Code | Meaning |
|---|---|
| P0300 | Random/Multiple Cylinder Misfire Detected |
| P0016 | Crankshaft Position – Camshaft Position Correlation (Bank 1 Sensor A) |
Guides that help
When it is more than a sensor
If a stretched chain has already jumped time and damaged valves, or low oil pressure has worn the engine, a repair can cost more than a replacement; see engine replacement cost and compare engines by code on our engines page.
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