DTC P0327: Knock Sensor Circuit: Description

WARNING: This page is about a different car, the 2003 Pontiac Sunfire, 2003 Pontiac Grand Am, 2003 Oldsmobile Alero, and 2003 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.

The Knock Sensor (KS) system enables the Powertrain Control Module (PCM) to control the ignition timing for the best possible performance while protecting the engine from potentially damaging levels of detonation. The KS is located on the intake side of the engine block. The KS produces an AC voltage signal that varies depending on the vibration level during engine operation. The PCM adjusts the spark timing based on the amplitude and frequency of the KS signal. The PCM receives the KS signal through a signal circuit. The KS ground is supplied by the PCM through a low reference circuit. The PCM uses the KS signal to calculate the average voltage and then assigns a voltage range value. The PCM should monitor a normal KS signal within the voltage range. If the PCM detects the KS signal outside of the voltage range, or the KS signal is not present, this DTC sets.