Circuit/System Description

WARNING: This page is about a different car, the 2007 GMC Sierra and 2007 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The knock sensor (KS) system enables the engine control module (ECM) to control the ignition timing for the best possible performance while protecting the engine from potentially damaging levels of detonation. The ECM monitors 2 separate KS, one on each side of the engine block. Each KS produces an AC voltage that varies, depending on the vibration levels detected during engine operation. The ECM adjusts the spark timing based on the amplitude and frequency of each KS signal. The ECM receives the KS signal through 2 isolated signals circuits for each KS. The control module learns a minimum noise level for each sensor, at idle speeds, and uses calibrated noise levels values for the rest of the RPM range. The ECM should monitor a normal KS signal within the noise channel.