Technician A says an air/fuel ratio sensor responds to minor changes in the air/fuel mixture. Technician B says that when an air/fuel ratio sensor is used on an OBD-II vehicle, both the upstream and downstream sensors must be air/fuel ratio type sensors. Who is correct?

Question

Quizplus · Accepted Answer

Technician A is correct because an air/fuel ratio sensor, also known as a wideband oxygen sensor, is designed to precisely measure the air/fuel mixture in real-time, allowing for minor adjustments to be made for optimal engine performance. Technician B is incorrect because it is not necessary for both the upstream and downstream sensors to be air/fuel ratio type sensors. The downstream sensor, often a traditional oxygen sensor, primarily monitors the efficiency of the catalytic converter rather than the air/fuel mixture.

Technician a Says an Air/fuel Ratio Sensor Responds to Minor