pin 8, code 13 states: "O2S (Lambda) control system operating at rich or lean limit"

which would seem to me to indicate a bad O2 sensor, but not code is showing up on the #2 pin, so I'm not sure if this is correct. Any ideas?

Also, I've been trying to find the exact location on where the oxygen sensor is on my car, and I know it's under the front passenger side of the car, but where exactly, and how do I gain access to it? Thanks

John

__________________
1995 E320 119,000 miles