Circuit Description

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 KS produces an A/C signal that varies with different engine speeds and loads. The ECM makes adjustments to the spark timing based on the amplitude and frequency of either KS signal. The ECM receives the KS signal through a signal circuit. The ECM supplies the KS ground through a low reference circuit. The ECM uses the KS to calculate the amount of normal engine noise for a wide range of engine speeds and loads. The normal engine noise that has been calculated and retained in the ECM memory is called the learned noise channel. The ECM compares the actual KS signal to the learned noise channel in memory. When the ECM determines that the KS signal is outside the limits of the learned noise channel, the ECM will retard the spark timing until the knock goes away. If the knock is such that the engine requires a large amount of spark retard and the ECM is unable to eliminate the knock, this DTC will set. DTC P0326 refers to either the bank 1 KS or the bank 2 KS.