Closed Loop Mode

The engine is in this mode of operation when none of the open loop engine operating conditions exist. The MCU causes the MC solenoid to vary the air/fuel mixture in reaction to the voltage input from the oxygen sensor located in the exhaust manifold.

The oxygen sensor varies in reaction to changes in the oxygen content of the exhaust gases. Since the oxygen content of the exhaust gases indicates the completeness of the combustion process, it is a reliable indicator of the air/fuel mixture entering the combustion chamber.