Knock Sensor: Testing and Inspection

Knock Sensor Diagnosis
Scan Tool Diagnosis
The GM Techline scan tool has several positions for diagnosing the Knock Sensor (KS) circuit.

^ KS activity indicates whether or not a knock signal is being detected by the knock sensors. The scan tool will display "YES" when a knock is detected.

^ Knock retard indicates the amount of spark the PCM is removing from the Ignition Control (IC) spark advance in response to the signal from the knock sensors.

^ Spark Indicates the amount of spark advance being commanded by the PCM on the IC circuit.

Diagnostic Trouble Code Diagnosis
Diagnostic Trouble Code (DTC) P0325 indicates that the KS module is malfunctioning or is missing. DTCs P0327 and P0332 indicates that a Knock sensor or Knock sensor circuit is malfunctioning. If these DTCs are set, refer to applicable DTC table.