P0326: Knock sensor 1 signal out of range (bank 1 or single sensor)
The knock sensor signal does not match what the ECU expects. It may be a loose or faulty sensor, its wiring or real engine noise.
| Code | P0326 |
|---|---|
| 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 P0326 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. Here the circuit works, but the signal is too strong, too weak or inconsistent with how the engine is running. It is sensor 1, on bank 1 or the only one.
Most common causes
- Sensor loose or tightened to the wrong torque
- Connector or wiring with poor contact or interference
- Poor quality fuel or lower octane than specified, causing real knock
- Mechanical engine noise (loose parts, play, mounts) that the sensor mistakes for knock
- Failed knock sensor
Symptoms
- Less power, especially under hard acceleration
- Slightly higher fuel consumption
- Engine warning light on
- Sometimes no noticeable symptoms
Can you drive with P0326?
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.
How to check it
Listen for a metallic rattle or pinking when accelerating in a high gear: if you hear it, there may be real knock and it is worth trying the fuel grade the manufacturer specifies.
How to read and clear P0326 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 P0326 with this same explanation and whether it’s confirmed, pending or permanent.
With Free you read this code with its short description for nothing, and clear it if the engine stores it over standard OBD. With Pro you get the full explanation, how the car was running when it was logged (revs, temperature, load) and clearing in every control unit.
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 the ITV. It’s all in how to read and clear fault codes and in the ITV and OBD.
Similar codes
- P0320 Engine speed input (ignition or distributor): circuit fault
- P0321 Ignition or distributor engine speed signal out of range
- P0322 No ignition or distributor engine speed signal
- P0325 Knock sensor 1 circuit fault (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)
- P0330 Knock sensor 2 circuit fault (bank 2)
- P0332 Knock sensor 2 circuit low input (bank 2)
- P0300 Random or multiple cylinder misfire
- P0301 Misfire detected in cylinder 1
- P0302 Misfire detected in cylinder 2
- P0303 Misfire detected in cylinder 3
P0326 is a generic code, so it means the same on any make, for example on BMW, Ford, Mercedes-Benz, Renault, Volkswagen, Volvo. See what Final OBD does on your car in makes and models.
What does code P0326 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. Here the circuit works, but the signal is too strong, too weak or inconsistent with how the engine is running. It is sensor 1, on bank 1 or the only one.
Can you drive with P0326?
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 P0326?
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, P0326 comes back.
Read it on your car
Final OBD reads the faults of every control unit for free, including each make’s own codes, and with Pro explains each one in plain English. Free clears engine faults at no cost.
Coming soon
Mid to late October 2026
If you want to try it in your car before anyone else, send us your email and we will add you as a tester.
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