I will look at the service manual I have, see if there are any tips on replacement. I am 99% sure there are 3 sensors, but will check the manual for sure, front and rear of the engine and near the catalytic converter.
It doesn't say anything, the wiring manual shows 3 sensors, 1- Heated oxygen sensor, Bank 1 sensor 2, the wire colors are Blk, Wht, Blk/Red, Brown. 2- Air fuel ratio sensor, Bank 1 sensor 1, wire colors Blue,Red,Green,Blk/Red. 3- Air fuel ratio sensor, Bank 2 sensor 1, colors Green, Blue, Blk/Red, Blk/White. Usually the sensor has the special high temp anti seize on it when you buy it, there is a special socket to fit over the sensor, but most times, a box wrench will work just fine, use some spray lube on it when you remove it, best to rock it back and forth than to turn it out if it begins to get stiff. You do not want the metal to gall, and the threads to get screwed up. Might try spraying the one you want to change with a penetrating oil the night before.... Hope this has helped. What is the code the OBDII is showing?
P1133 A/F Sensor Circuit Responce Malfunction, says to check:
1- Open or Short in A/F sensor circuit
2- A/F sensor
3- Air Induction system
4- Fuel Pressure
I agree with you in that you should check/replace the Bank1 sensor1, which ever one that is...LOL!!!!.... look at the previous post for the wire colors. When one of mine went bad, I also had a traction control and skid control lights light up with the check engine light...... I do not think the 99's had that stuff in them.......
Mine was the front one, easy to get at with the hood open...... I bought a code reader off of ebay a while back before I had my manuals, so I looked the code up online.... the manuals are sweeeet...... I see them every once in a while on ebay, and they are worth it if your doing your own work.
a friend of mine has a 99 rx300 awd wiith about 67k on it and about 2 months ago i got a check engine light, it said bank 1 lean condition. a friend of mine works on toyotas and he said that it would be the bank 1 a/f sensor so i replaced it and the light keeps coming back. she has a k&n drop in filter in the car. after the light went on, i also cleaned the maf sensor and the throttle bodies. any suggestions on wat else it could be?? my friend said it could also be the maf itself.