Why are there more than 1 air-fuel sensor in a Toyota RAV4?

A Toyota RAV4 typically has more than one air-fuel sensor to optimize engine performance and emissions control. These sensors monitor the air-fuel mixture at different points, such as before and after the catalytic converter, allowing the engine control unit to make real-time adjustments for efficiency and to ensure proper combustion. This setup helps maintain optimal fuel economy, reduce emissions, and enhance overall engine performance. Additionally, having multiple sensors provides redundancy and improves the vehicle's diagnostic capabilities.