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 AC signal that varies at all engine speeds and loads. The ECM makes adjustments to the spark timing based on the amplitude and frequency of the KS signal. The ECM receives the KS signal through a signal circuit. The KS ground is supplied by the ECM through a low reference circuit. The ECM uses the KS to calculate the amount of normal engine noise (a noise channel) for a wide range of engine speeds and loads. The ECM compares the actual KS signal to the learned noise channel. When the ECM detects a KS signal that varies outside of the noise channel, the ECM will retard the spark timing until the knock goes away. If the knock is such that the vehicle operates on large amounts of spark retard and the ECM is unable to eliminate the knock, this DTC will set. DTC P0326 refers to the bank 1 sensor. DTC P0331 refers to the bank 2 sensor.