Should be on the right side in front of the Cat converter.
I was getting the P0134 and a check engine light myself and ordered an OEM O2 sensor. I didn't want one of those "universal" types that you have to splice the wires.
But here's the funny thing. While I was waiting for the O2 sensor to be delivered, I tried a couple bottles of STP gas treatment. I had read that sometimes dirty injectors give the O2 sensors trouble. The P0134 disappeared, my check engine light went out, and I sailed through emissions inspection. I returned the new O2 sensor unopened.
Well I turned the CEL off and then a day later it came back on and scanned it again and showed up the same code. Then, next day it went off by itself and so far no CEL, but will scan and see if there is anything pulling up on the scanner.
The O2 sensor, is that the one goes towards the engine block?
Yes, sensor 1 is the one closer to the engine, sensor 2 is after the cat converter, bank 1 is right side, bank 2 is left side. P0134 is the only code that I have ever got in over 14 years of owning our Catera.
Finally got a chance to replace the O2 sensor and turned the CEL off, test drove the car refueled it and the CEL came on again, scanned it and shows the same code "P0134 - 02 Sensor Circuit No Activity Detected (Bank 1 Sensor 1)". Now what should I look for?
Why worry about it? Are you not passing inspection? My car has a permanent P0134. but still passes emissions. I don't ever remember not having it since I bought my scanner over 10 years ago.
Sometimes it gets so bad, it turns on the CEL, but it even that has not happened in a couple of years. When it does get so bad that it turns on the CEL, I can usually get rid of it with a few tanks with STP gas treatment.