My car is RX300 2001. The A/F sensor Bank1 Sensor1 is supposed to on the side of the engine that is further away from the radiator. There are quite a few wires and connectors. I cannot tell which one is the A/F sensor. Is it easy to reach and to take out?

Could any experts give me hints or pictures?

 

here it is: under the car from the firewall side of the engine....soak it with PB Blaster first and then use An oxygen sensor socket or 6 sided box wrench....

 

If you have had the dreaded P0171 check engine light and have had it diagnosed as possible A/F sensor problem, try spraying th MAF sensor with cleaner as suggested by LexMex. It worked for me. It may take up to 3 days after spraying and cleaning for the ECU to remove teh check engine light. I tried to reset the ECU but was unsuccessful. Worth trying first before unloading $150 or more for a new A/F sensor.

 

Thank you! thomas1 and rlusna78. The picture is very helpful. I will try to get to it from underneath.

In case this may be helpful to others,

The ODBII code I got was P1135. I got a DTC document for P1135 by googling P1135 and rx300. It suggested me to check 3 things.
1) the voltage between terminals HAFL, HAFR of ECM connector and body
ground.
2) the resistance of air/fuel sensor B1S1
3) air/fuel heat circuitry relay.

The relay is fine. And the voltage on HAFR is only 2v, which means ECM did not give a false alarm. I am trying to check the resistance now.