P0334 Knock sensor: signal drops out at times (sensor 2, bank 2)

By: Diagno editorial team · Updated: 2026-10-15

P0334 means: Knock sensor: signal drops out at times (sensor 2, bank 2). The knock sensor listens for engine knock. Drive gently and have the car checked soon. The most common repair costs about €45–90 in Estonia, depending on make and model. The most common cause: connector loose, damp or corroded.

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. The signal drops out now and then. The most common cause is a loose connector or a chafed wire. 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

1. 1Connector loose, damp or corroded · Wiring or connector repair €45–90
2. 2Wire broken or chafed · Wiring or connector repair €45–90
3. 3Faulty sensor · Sensor replacement €80–160
4. 4Engine computer fault (rare) · Control unit check and software €150–300

Repair difficulty: Moderate

What you can check yourself

First look at the connector and wiring: anything loose, melted or green with corrosion? 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

1. We read the fault data on the diagnostic tool and check whether the fault is constant
2. We measure the circuit's supply, ground and signal
3. We repair the wire or replace the connector
4. If the wiring is fine, we replace the sensor

Standard SAE description: Knock Sensor 2 Circuit Intermittent (Bank 2)