Operation

The Knock Sensor (KS) detects abnormal vibration (spark knocking) in the engine and is located on the engine block near the cylinders. The sensor produces an AC output voltage which increases with the severity of the knock. This signal voltage is input to the PCM. The PCM contains integrated knock sensor 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. The PCM then adjusts the IC timing to reduce spark knock. DTC P0325 KS Module Performance and DTC P0327 KS Circuit are designed to diagnose the PCM, the knock sensor, and related wiring, so problems encountered with the KS system should set a DTC.