Circuit Description

PCM contains integrated Knock Sensor (KS) diagnostic circuitry. An input signal from KS is used to detect engine detonation, allowing PCM to retard ignition timing based on amplitude and frequency of KS signal being received. KS produces an AC signal under all engine operating conditions. During engine operation, PCM calculates average voltage of KS signal. If PCM malfunctions in a manner which will not allow proper diagnosis of KS circuit, DTC P0325 will set.