P0331 indicates the engine control module has detected a signal from the knock sensor on bank 2 that is outside the expected voltage or frequency range. This prevents the computer from properly adjusting ignition timing to prevent engine knocking. It usually points to a sensor fault or wiring issue rather than internal engine damage.
Internal sensor failure is the most common cause of range or performance codes.
Heat and vibration often crack insulation or break wires near the sensor body.
Poor contact at the plug can interrupt the signal voltage returning to the computer.
Worn bearings or ticks can mimic knock vibrations and confuse the sensor.
Heavy deposits can cause pre-ignition that the sensor detects as a circuit performance issue.
Internal computer failure is possible but should only be considered after all other causes are ruled out.
Extended driving is not recommended as incorrect timing can damage the engine.
No, PCM failure is rare; replace the sensor or fix wiring first.
It refers to the engine side that does not contain cylinder number one.
Yes, low octane fuel can cause knocking that confuses the sensor circuit.