P0334
Knock/Combustion Vibration Sensor B Circuit Intermittent
Ignition / knock sensor
Generic OBD-II
Medium
What it means
P0334 means the knock-sensor B circuit is dropping in and out. This sensor detects detonation so the ECM can retard ignition timing and protect the engine. With an intermittent B-sensor signal the ECM falls back to conservative timing — you may lose a little power and economy, but it won't leave you stranded.
Medium
Can I keep driving? Driveable — the ECM falls back to conservative timing when the B knock signal drops, so you may lose a little power and economy, but it won't leave you stranded.
Common symptoms
What you'll notice
- Check-engine light on
- Slightly reduced power or acceleration
- Poorer fuel economy
- Occasional knock or ping under load
Common causes
Most likely first
- Intermittent break in the knock-sensor B wiring or connectorLikely
- Faulty knock sensor BCommon
- Loose or corroded connector or sensor mountingCommon
- Excessive engine vibration read as knockLess often
- Faulty ECM (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data to see when the dropout occurs.
- Wiggle-test the sensor B harness and connector for an intermittent open.
- Check the sensor is torqued correctly to clean bare metal.
- Replace knock sensor B if the signal is erratic.
- If wiring and sensor check out, evaluate the ECM. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0334?+
Yes — the ECM protects the engine with safe timing. Sustained real detonation can cause damage, so don't leave it indefinitely.
Can I just clear P0334?+
It'll clear but returns when the intermittent fault recurs; find the loose connection or failing sensor.
Related codes
Often seen with P0334
Read & clear P0334 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX