Circuit Description

WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. 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 at the left side of the engine block. The KS produces an AC voltage that varies depending on the vibration level during engine operation. The PCM adjusts the spark timing based on the amplitude and the frequency of the KS signal. The PCM receives the KS signal through a signal circuit. The KS ground is supplied by the engine block through the sensor housing. The PCM uses the KS signal to calculate an average voltage range value. If the system is operating normally, the PCM should monitor the KS voltage varying above and below the voltage range. If the PCM detects the KS signal voltage within the voltage range, or the KS signal is not present, this DTC will set.