Location of System 1 Bank 1 O2 Sensor - 1998 Toyota Avalon

SOURCE: location of bank 1 sensor 1 o2 sensor

Should be in the manifold on the back side closest to the firewall.

SOURCE: location of a o2 sensor 2001 nissan maxima

bank 1 refers to the side of the engine that #1 cylinder is on , and sensor 2 refers to downstream , after the catalytic converter. , this link shows bank 1 on a 2001 nissan maxima V6 being on the firewall side . if you had a 4 cylinder it would be downstream after the catalytic converter .

http://www.autozone.com/N,26200242/shopping/specsSelect.htm

SOURCE: obd code P0135 on a lexus ls400

usually your first sensor is located on the exhaust manifold

SOURCE: location of the bank 1 sensor 2 O2 sensor on a 2001 ford escape

B1 means the sensor is located on the same bank of the engine that has the #1 cylinder. B2 is located on the opposite bank.
S1 means the sensor is located BEFORE the catalytic converter
S2 means the sensor is located AFTER the catalytic converter

You didn't say which engine you have, so I've included the diagrams of both 4 cyl and 6 cyl so you can see the banks

SOURCE: have p0130 and p0133 codes 98 toyota tacoma

I would check the O2 sensor, and if it checks bad, replace it, and clear the trouble codes. If the light comes back on, you may need to check further. .