Knock Sensor: Testing and Inspection

SCAN TOOL DIAGNOSIS
The Tech 1 scan tool (or equivalent) has several positions to check when diagnosing the Knock Sensor (KS) circuit. It will indicate when knock is present. "Knock signal" is used to monitor the input signal from the knock sensor. This position should display "YES" to indicate when a knock is being detected. "Knock retard" is the indication of how much the Powertrain Control Module (PCM) is retarding the spark.

DIAGNOSTIC CHARTS
Diagnostic Trouble Code (DTC) 43
Problems encountered with this circuit should set DTC 43, Knock Sensor Circuit. This DTC is designed to diagnose the knock sensor circuit. Powertrain Controls - ECM/PCM

Chart C-5
If no DTC 43 was set but the KS system is suspected, refer to Chart C-5 Knock Sensor (KS) System Check. Chart C-5 Knock Sensor (KS) System Check