Microcomputer Control Unit (MCU): Notes

The MCU is a microprocessor unit that monitors oxygen sensor voltage and, based upon the mode of engine operation, generates an output control signal for the M/C solenoid. In this manner, the MCU provides the correct air/fuel ratio for all engine operating conditions.

Engine operating conditions are relayed to the MCU by the data sensors. From this information, the MCU determines the operating mode for the engine (open loop or closed loop).