P0331 Knock sensor: reading or operation not right (sensor 2, bank 2)
P0331 means: Knock sensor: reading or operation not right (sensor 2, bank 2). The knock sensor listens for engine knock. Drive gently and have the car checked soon. The repair usually costs about €60–350 in Estonia. The most common cause: faulty or loose sensor. Other possible causes: sensor wire or connector, fuel octane too low.
What it means
The knock sensor listens for engine knock. If its signal is wrong, the computer retards the ignition to be safe and the engine loses power. There is a signal, but the reading or operation isn't plausible. The cause may be the part itself or a real mechanical fault. Bank 2 is the side of a V engine without cylinder 1.
What you may notice
- Engine light on
- Less power
- Slightly higher fuel consumption
What could be wrong
- 1Faulty or loose sensor
- 2Sensor wire or connector
- 3Fuel octane too low
- 4Real knock (carbon build-up, overheating)
Repair difficulty: Moderate
What you can check yourself
Fill up with the right octane fuel. The sensor is often on the block under the intake, so it may be hard to reach. You can check the simple things yourself, but the repair is best done in a workshop.
How we fix it
- We read the sensor on the diagnostic tool and compare it with other sensors
- We check the connector, supply and ground
- We repair the wiring or replace the sensor
Standard SAE description: Knock Sensor 2 Circuit Range/Performance (Bank 2)