System Description

Some of components such as vehicle speed sensor. send information along to powertrain control module (PCM)/engine control module (ECM) in form of analog data. The PCM/ECM must then convert analog data to serial data in order to analyze it. The PCM/ECM continuously monitors this activity every 125 milliseconds and checks for active malfunction codes on inputs to A/D MUX that are shorted high. This Diagnostic Trouble Code (DTC) will set when an active malfunction is present that affects A/D MUX diagnostic.