Operation

The knock sensor detects abnormal vibration (spark knocking) in the engine. The knock sensor is mounted in the engine block near the cylinders and produce an AC signal under all engine operating conditions. The Powertrain Control Module (PCM) contains integrated Knock Sensor (KS) diagnostic circuitry which uses the input signals from the knock sensors to detect engine detonation. This allows the PCM to retard Ignition Control (IC) spark timing based on the amplitude and frequency of the KS signal being received.