Closed Loop

Specific values for the above conditions exist for each different engine, and are stored in the Electronically Erasable Programmable Read Only Memory (EEPROM). When these values are met, the system goes into Closed Loop operation. The PCM calculates the air/fuel ratio, injector on-time, based on the signal from the O2S. This allows the air/fuel ratio to stay very close to 14.7:1.