What is the difference between air/fuel sensor and oxygen sensor?

Question

Hello, I am unsure of the exact number, but my car recently pulled codes for both a faulty upstream oxygen sensor (I know what this is) and a faulty air/fuel sensor (I do not fully understand this).  Other than replacing the o2 sensor, how can I fix this so that I can pass inspection?

The car is a 1998 toyota camry.
Thanks!

Answer 1

The difference between a 02 and a AF a 02 sensor is a narrow band and a A/F is a wide band, the 02 sensor is slow to adjust the fuel control, and the wide band is fast, to adjust the fuel control. Plus if your vehicle calls for a wide band these are always the upstream sensor , all downstream are narrow band downstream which  only monitor a catalytic convertor for degradation , you only set a upstream 02 sensor code with different code numbers