P0330: Knock/Combustion Vibration Sensor B Circuit
A generic powertrain (engine and transmission) trouble code, same meaning on every brand.
Yes - reduced power and economy until the sensor is trusted again.
Symptoms
- Reduced power under load
- Worse fuel economy
- Check engine light
Likely causes, most common first
- Bank 2 knock sensor failed
- Wiring or connector fault
- Sensor mounting loose or corroded
- Genuine detonation from fuel quality or carbon buildup
Read P0330 yourself before paying for diagnosis
A basic Bluetooth OBD-II scanner ($20-40) plugs into the port under the dashboard and shows this code with live sensor data on your phone - useful both for confirming the fix and for talking to a shop from an informed position.
What is going on and how it gets diagnosed
P0330 covers the second knock sensor, fitted to engines with two cylinder banks so that each bank has its own ear. Losing one of the two leaves the computer half deaf, and it responds conservatively for the whole engine rather than for one bank.
If the sensor and wiring check out, consider what the sensor may be hearing. Low-octane fuel in an engine that wants premium, or carbon deposits raising the effective compression ratio, both produce real detonation - in which case the code is doing its job and the fix is fuel or decarbonising rather than a part.
Repair options and cost
Typical US independent-shop ranges, parts and labor. Dealers run higher; regional labor rates vary.
Frequently asked questions
Can I drive with P0330?
Yes - reduced power and economy until the sensor is trusted again.
How much does it cost to fix P0330?
Typical US repair costs range from $80 for the simplest fix (knock sensor) to $800 in the worst case. The right number depends on which cause your car has - see the causes list.
Related codes
The codes closest to P0330. They often appear together, and telling them apart is usually what narrows the diagnosis.
Definition per SAE J2012 standard nomenclature. Symptoms, causes and costs are editorial guidance - always confirm with a diagnosis of your specific vehicle.