What is air fuel sensor heater circuit bank 2 sensor 1 of rav4 2001?

Answer 1

If you stand looking at your engine, there's a heatshield at the front, over the exhaust manifold. Theres a hole in the front of the heatshield and the AF Sensor is fitted in there with a cable coming from the top of it.

The heater circuit isn't needed, your car will run fine without it but your engine light won't go out. You need to change the sensor and have it reset. It's easy enough to change, simply unplug the sensor, take off the heatshield and remove the sensor with a 22mm ring or box spanner. Replace with a new sensor and go and have it reset. It helps if you know someone with an OBD reader. But be warned, dealers will take you to the cleaners for this job. It takes about 20 minutes. I used universal sensors to relace all 4 of mine, I had to do some wire splicing but I'd say it took about 30 minutes per sensor including splicing...