P0325: Knock sensor 1 circuit fault (bank 1 or single sensor)
The ECU has found an electrical fault in the knock sensor circuit. Usually the connector, wiring or the sensor itself.
| Code | P0325 |
|---|---|
| System | Engine and transmission |
| Group | P03xx, Ignition and misfires |
| Type | Generic: it means the same on every make |
| Can you keep driving? | With care |
What P0325 means
The knock sensor is bolted to the engine block and works like a microphone: it picks up the vibration of knock (detonation, fuel burning at the wrong moment and hammering the pistons). When it hears it, the ECU retards the ignition to protect the engine. This code points to a fault in the sensor’s electrical circuit (wire, connector or sensor). It is sensor 1, on bank 1, or the only one if the engine has just one.
Most common causes
- Loose, dirty or corroded sensor connector
- Broken or chafed sensor wire (often routed under the intake manifold)
- Sensor not tightened properly to the block
- Failed knock sensor
- ECU fault (rare)
Symptoms
- Less power, especially under hard acceleration
- Slightly higher fuel consumption
- Engine warning light on
- Sometimes no noticeable symptoms
Can you drive with P0325?
With care You can drive, as the ECU usually retards the ignition as a precaution, but the engine is less protected if real knock occurs. Avoid working it hard and get it checked soon.
Open the bonnetthe in-depth explanation
How to check it
If your scan tool shows knock retard, watch it live: if it sits at maximum even though the engine sounds fine, the ECU has gone into protection mode because of the sensor fault.
How to read and clear P0325 with Final OBD
Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see P0325 with its description and whether it’s confirmed, pending or permanent.
If the engine stores it over standard OBD, with FREE you read this code with its explanation for nothing and clear it. With PRO you also read the faults of every control unit and clear them in all of them.
Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before an inspection. It’s all in how to read and clear fault codes and in inspections and OBD.
Similar codes
- P0321 Ignition or distributor engine speed signal out of range
- P0322 No ignition or distributor engine speed signal
- P0323 The crankshaft position or engine speed sensor circuit fails intermittently
- P0324 There is a fault in the engine knock control system
- P0326 Knock sensor 1 signal out of range (bank 1 or single sensor)
- P0327 Knock sensor 1 circuit low input (bank 1 or single sensor)
- P0328 Knock sensor 1 circuit high input (bank 1 or single sensor)
- P0329 The circuit signal from knock sensor 1 on bank 1 is intermittent
- P0300 Random or multiple cylinder misfire
- P0301 Misfire detected in cylinder 1
- P0302 Misfire detected in cylinder 2
- P0303 Misfire detected in cylinder 3
To understand it properly
We explain how that system works, with drawings and no waffle, in our mechanics guide: Knock and pre-ignition.
What does code P0325 mean?
The knock sensor is bolted to the engine block and works like a microphone: it picks up the vibration of knock (detonation, fuel burning at the wrong moment and hammering the pistons). When it hears it, the ECU retards the ignition to protect the engine. This code points to a fault in the sensor’s electrical circuit (wire, connector or sensor). It is sensor 1, on bank 1, or the only one if the engine has just one.
Can you drive with P0325?
You can drive, as the ECU usually retards the ignition as a precaution, but the engine is less protected if real knock occurs. Avoid working it hard and get it checked soon.
How do you clear P0325?
With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, P0325 comes back.
Read it on your car
Final OBD reads and clears engine faults through standard OBD for free, each one explained in plain English. With PRO it also reads the faults of every control unit, each make’s own codes included, and clears them in all of them.
