P0327: Knock sensor 1 circuit low input (bank 1 or single sensor)
The ECU sees a knock sensor signal that is too low. Almost always electrical: a broken or earthed wire, the connector or the sensor itself.
| Code | P0327 |
|---|---|
| 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 P0327 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. Low input means the ECU is reading a voltage below what is possible, almost always because of an electrical problem. It is sensor 1, on bank 1 or the only one.
Most common causes
- Sensor connector unplugged or corroded
- Broken wire or wire shorting to earth
- Sensor loose on the block, so it barely picks up vibration
- 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 P0327?
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
Clear the code and drive normally with some acceleration: if it returns straight away the fault is permanent (wire or sensor); if it takes days, suspect a poor contact at the connector.
How to read and clear P0327 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 P0327 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
- 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)
- P0326 Knock sensor 1 signal out of range (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)
- P0335 Crankshaft position sensor A circuit fault
- P0300 Random or multiple cylinder misfire
- P0301 Misfire detected in cylinder 1
- P0302 Misfire detected in cylinder 2
- P0303 Misfire detected in cylinder 3
P0327 is a generic code, so it means the same on any make, for example on Audi, Fiat, Mazda, Opel / Vauxhall, Peugeot, Toyota. See what Final OBD does on your car in makes and models.
What does code P0327 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. Low input means the ECU is reading a voltage below what is possible, almost always because of an electrical problem. It is sensor 1, on bank 1 or the only one.
Can you drive with P0327?
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 P0327?
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, P0327 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.
info@finalobd.com