Circuit Description

The Knock Sensor (KS) produces an AC voltage at all engine speeds and loads. The PCM then adjusts the spark timing based on the amplitude and frequency of KS signal. PCM uses KS signal to calculate the average voltage, then PCM assigns a voltage value. The PCM checks the knock sensor and related wiring by comparing actual knock signal to assigned voltage range. A normal KS signal should stay within the assigned voltage range. This DTC will set if PCM malfunctions in a manner that will not allow proper diagnosis of KS system.