Diagnostic article Generic OBD-II
P06B7: The knock-processor test is not a measurement of engine knock
Understand the internal 20 kHz test-circuit assessment behind GM P06B7 and why valid engine operating history matters.
Read before applying this article
Documented application
2025 GM 03B documented monitor only. Vehicle, engine and controller calibration applicability must be established separately; no model fitment is inferred from the file.
The code alone does not identify a failed part or establish that a vehicle is safe to drive. Confirm the vehicle, reporting module and applicable service procedure.
P06B7 names internal control-module knock-sensor processor 2 performance. The cited GM strategy checks an internal test circuit used by a particular 20 kHz open-circuit diagnostic method. It is not a finding that the engine is experiencing unusually strong combustion knock.
Frequency-domain test evidence has its own prerequisites
The controller examines a defined part of the frequency-analysis output against calibration-specific internal-test thresholds. The source describes two threshold cases and a first-order filter with a weight coefficient of 0.015, updated each engine event. A single unfiltered sensor-voltage observation cannot reproduce that filtered internal assessment.
The engine must have accumulated more than 161 revolutions within the eligible speed range for the key cycle. That range is above 650 and below 4,250 rpm, with additional airflow and diagnostic-enable conditions. Merely being started is not the same as having accumulated the required valid operating history.
Distinguish internal-test performance from external sensor interpretation
Retain the applicable test case, eligible revolution history and filtered diagnostic result. The code's processor-2 designation selects the documented internal channel; it does not establish a physical sensor mounting location on an unspecified engine.
The numerical signal boundaries are calibration references in supporting tables, so they should not be replaced with guessed universal voltage limits. The summary does not determine whether a controller must be replaced or authorize interpreting the result as mechanical detonation. Further isolation requires the correct diagnostic implementation and service information.
Source and applicability
2025 GM 03B documented monitor only. Vehicle, engine and controller calibration applicability must be established separately; no model fitment is inferred from the file. GM PDF, physical page 589.
Article source documents
Source checks describe how the text was prepared; they do not certify a diagnosis or confirm compatibility with every vehicle using this code.
Original code reference
Dictionary definition
Internal Control Module Knock/Combustion Vibration Sensor Processor 2 Performance
This definition retains its original catalog scope. The article above is limited to its explicitly documented application.
Reference scope
Generic OBD-II definition.
A manufacturer label does not establish the model, year, engine or module to which a diagnosis applies. Read the safety and diagnostic limits.
Definition source
- DTC Database: pinned community code definitions
Source checked · MIT