P032A: Knock-sensor C open-load detection uses accumulated evidence

P032A is a circuit fault for knock or combustion-vibration sensor C. GM’s implementation identifies the channel as knock sensor 3 and describes an open-load detection strategy based on an integrated diagnostic result.

The monitor accumulates rather than reacts once

The source gives 30 events and two-trip reporting. It also says the check runs every 15–120 seconds as a function of engine speed. That schedule explains why an immediate absence of the code after clearing it does not establish that the circuit passed a completed monitor.

Eligibility includes knock-sensor PWM duty above 50 percent, engine speed between 800 and 5,000 rpm, and engine load between 13 and 160 percent. Short-to-ground and short-to-battery diagnostics must be enabled. The integrated numerical boundary is an internal result, not a resistance value to apply at the sensor.

Keep circuit detection separate from actual knock

This row does not say that combustion knock itself exceeded a safe amount. It evaluates whether the sensor circuit exhibits the expected diagnostic behavior. A quiet engine sound is therefore not a substitute for circuit evidence.

Confirm how sensor 3 maps to the installed engine before selecting a connector. The code does not localize an interruption or establish whether the sensor, harness or controller path caused the result. Use the vehicle-specific circuit procedure and monitor-completion information to verify the fault, rather than treating one instantaneous sensor reading as the whole test.

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 601.