P0333
Knock/Combustion Vibration Sensor B Circuit High
Ignition timing
Generic OBD-II
Medium
What it means
P0333 means the second knock sensor (bank 2) is sending a higher-than-expected signal to the ECM. Because the computer relies on this sensor to detect knock and fine-tune ignition timing, it retards timing as a safeguard and you may notice slightly less power. It is an electrical circuit fault — it will not prevent the engine from starting.
Medium
Can I keep driving? Usually driveable — with the knock signal lost the ECM retards timing to stay safe, costing a little power and economy but posing no immediate danger.
Common symptoms
What you'll notice
- Check-engine light on
- Slightly reduced power or acceleration
- Possible knocking or pinging under load
- Small drop in fuel economy
Common causes
Most likely first
- Failed knock sensor B (bank 2) reading highLikely
- Signal wire shorted to voltage or open in the circuitCommon
- Loose or corroded connector at the sensorCommon
- ECM fault (rare — check the sensor and wiring first)Less often
How to diagnose & fix
Work through it in order
- Scan and read freeze-frame data to confirm the fault is on the bank 2 (sensor B) knock circuit.
- Inspect the sensor connector and harness for a short to voltage, chafing, or corrosion.
- Measure the knock sensor's resistance and check its mounting torque.
- Compare the signal to the other bank's sensor to isolate a bad sensor from wiring.
- Replace knock sensor B if it is out of range with good wiring. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0333?+
Yes, short-term. You lose a little performance because the ECM retards timing, but the engine is not at immediate risk. Repair it before sustained hard driving.
Can I just clear P0333?+
It comes back once the ECM re-checks the circuit. The high signal has to be traced to the sensor or wiring and fixed.
Related codes
Often seen with P0333
Read & clear P0333 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