P0325 Knock Sensor 1 Circuit (Bank 1)
P0325 is a generic OBD2 powertrain code. It means “Knock Sensor 1 Circuit (Bank 1)” — the same on every make and model, because the definition comes from the SAE J2012 standard rather than from the carmaker.
Ask the AI about P0325 on your car- System
- Powertrain (P)
- Code type
- Generic (SAE)
- Range
- P03xx
- Urgency
- Moderate
What P0325 means
The knock sensor is a small microphone bolted to the engine block that listens for detonation, so the computer can retard the ignition before knock damages the pistons. The computer found a fault in the circuit of knock sensor 1 on bank 1 (P0325) or sensor 2 on bank 2 (P0330), or the signal too low (P0327) or too high (P0328).
Symptoms
- Often nothing but the lamp
- Less power and worse fuel economy — the computer retards the timing as a precaution
- Pinging under load if the protection isn’t working
Most likely causes
- A damaged connector or wiring — often under the intake manifold, where coolant or oil can reach it
- A failed sensor
- A sensor not tightened to the specified torque
What to check first
- Inspect the wiring and the connector
- Check that the sensor is tightened to specification
- Replace the sensor if the circuit checks out
Can I keep driving with P0325?
Drivable — plan the repair soon
Yes, gently. Until it’s fixed avoid heavy loads and fuel of a lower octane than specified — the engine’s knock protection may not be working.
What the wording tells you
The wording names a fault in the component’s circuit without saying more. Check the connector, the wiring and the fuse, and test the component, before replacing it.
Bank 1: engines with two rows of cylinders — V6, V8, boxer — have two banks. Bank 1 is the side that holds cylinder 1, bank 2 the other side; an inline engine has only bank 1.
How P0325 breaks down
Powertrain. Engine, transmission, fuel and emissions — the codes behind the check engine lamp.
Generic code: defined by SAE, the same on every make.
Ignition system & misfire.
The specific fault within this range.
Where to look: Ignition system & misfire
Misfire detection, ignition coils, crankshaft and camshaft position sensors and knock sensors. The engine computer detects misfires from dips in crankshaft speed, so this area often reports a problem that starts elsewhere — in the fuel supply or in compression.
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Frequently asked
What does P0325 mean?
P0325 is a generic OBD2 powertrain code. It means “Knock Sensor 1 Circuit (Bank 1)” — the same on every make and model, because the definition comes from the SAE J2012 standard rather than from the carmaker. The knock sensor is a small microphone bolted to the engine block that listens for detonation, so the computer can retard the ignition before knock damages the pistons. The computer found a fault in the circuit of knock sensor 1 on bank 1 (P0325) or sensor 2 on bank 2 (P0330), or the signal too low (P0327) or too high (P0328).
Can I drive with P0325?
Yes, gently. Until it’s fixed avoid heavy loads and fuel of a lower octane than specified — the engine’s knock protection may not be working.
What causes P0325?
A damaged connector or wiring — often under the intake manifold, where coolant or oil can reach it; A failed sensor; A sensor not tightened to the specified torque.
How do I clear P0325?
Fix the cause first, then clear it with any OBD2 scanner or app. Once the fault is gone the car also clears it on its own: the check engine lamp goes off after the self-test passes on three drive cycles in a row, and the stored code ages out after about 40 warm-ups. Clearing without a repair only hides it for a while — and resets the readiness monitors an emissions inspection looks at.
Is P0325 the same on every car?
Yes. P0325 is a generic SAE J2012 code, so its definition is identical on every make and model. What differs is the cause behind it and the repair procedure, which depend on the engine — that’s why the assistant on this page asks for your car.
Guides
Definitions: the generic SAE J2012 codes from Brimly’s offline dictionary (data version 2026.09). Causes and advice are general guidance for all makes — the service information for your car has the last word.