Monitor Description

The ECM continuously monitors its internal processors (CPUs), Air Fuel Ratio (A/F) sensor transistors and Heated Oxygen (HO2) sensor transistors. This self-check ensures that the ECM is functioning properly. This is diagnosed by internal "mirroring" of the main and sub CPUs to detect processor errors. If outputs from the processors deviate from the standards, the ECM will illuminate the MIL and set the DTC immediately.