Circuit Description

Knock Sensor (KS) produces an AC voltage at all engine speeds and loads. PCM then adjusts spark timing based on amplitude and frequency of KS signal. PCM uses KS signal to calculate average voltage. Then, PCM assigns a voltage value. PCM checks KS and related wiring by comparing actual knock signal to assigned voltage range. A normal KS signal should stay outside assigned voltage range. DTC P0325 will set if PCM malfunctions in a manner that will not allow proper diagnosis of KS system and related wiring.