P0330: Knock sensor B: circuit malfunction.
Meaning, symptoms, causes and checks
P0330 concerns knock-sensor B circuit integrity. Some systems call it sensor 2/bank 2, but verify location with OEM data. The code alone does not prove actual knock or internal engine damage.
Affected system: Powertrain
Symptoms
- Engine lamp, sometimes without audible knock.
- Reduced power or increased consumption if the fallback strategy alters ignition timing.
Possible causes
- Open/shorted wiring or corroded connections; the effect depends on circuit bias.
- Damaged or incorrectly mounted sensor; consider ECM only after isolating the circuit.
What to check
- Record codes/freeze-frame; locate sensor B and its physical bank using OEM diagrams.
- Check mounting, contact surface and specified torque; do not overtighten as a test.
- Inspect corrosion and shielding; distinguish signal wires from designated shield/ground connections.
- With modules isolated as instructed, test opens/shorts and compare circuit bias against engine specifications.
- Evaluate signal with scan tool/scope under specified conditions; isolate sensor from wiring before diagnosing the implausible reading.
Also written as: P0330-00, P033000, PO330 (some scan tools add the fault-type byte, e.g. -00).