P0330: Knock sensor B circuit monitoring waits for repeated eligible events

P0330 is the knock-sensor B circuit code. GM’s implementation names sensor 2 and assesses open-load evidence through an integrated diagnostic result. The code is therefore more specific than a general complaint that the engine’s knock signal looks unusual.

An open-load result is accumulated

The source uses a 30-event qualification and two-trip reporting. It describes a monitoring schedule of every 15–120 seconds depending on engine speed. A short test immediately after clearing the code may not include enough eligible observations to confirm a pass.

The enable window includes engine speed above 800 and below 5,000 rpm, engine load above 13 and below 160 percent, and sensor PWM duty above 50 percent. The short-circuit diagnostic functions must also be enabled.

Interpret completion as well as presence

Record whether the open-load monitor actually ran under those conditions. A code that stays absent while the assessment is inhibited supplies less evidence than a completed successful check.

The internal integrated threshold is not a resistance specification for an unplugged sensor, and the source does not establish a physical connector location from “sensor 2.” The matching vehicle information must identify the channel and approved circuit test. P0330 narrows the issue to open-load diagnostic behavior; it does not independently locate the interruption or prove that actual combustion knock is occurring.

Source and applicability

This explanation covers the cited GM monitor, not every vehicle carrying this code. The application-matrix filename does not resolve cleanly to this file, so no model or engine fitment is assigned. GM diagnostic table, PDF page 603.