Circuit Description
WARNING: This page is about a different car, the 2004 GMC Sierra and 2004 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The powertrain control module (PCM) monitors a knock sensor (KS) in order to determine if detonation is present. The KS produces an AC voltage at all engine speeds and loads. The powertrain control module (PCM) then adjusts the spark timing based on the amplitude and frequency of the KS signal. The PCM uses the KS signal to calculate the average voltage and then assigns a voltage range value. The PCM should monitor the KS signal within the assigned voltage range. This diagnostic trouble code (DTC) will set if the KS signal is outside the assigned voltage range or the KS signal is not present.