Well i got a new o2 sensor to replace sensor 2 which i believe is the one after the cataylic converter. I tried to get the old one out. I unplugged it and couldnt seem to get it out with the loaner tool. So i decided to start the car and warm it up to expand the exhaust and see if it would come out. So i plugged he O2 sensor in and magic, no engine light or anything. Maybe a lose connection what does everyone think? The car was reading code 21, got a engine light diagnostic, and it said 02 sensor bad circuit. I did run through some water due to the hurricane.

 

A bad o2 sensor will not always cause the CEL light to stay on. It may come on for 2 days then dissappear for a week. I'd keep the new o2 sensor for a few weeks before returning it just to make sure its fixed

 

Wait awhile to see if it pops up again. Could be that the connection wasn't good in the first place.