I need help today...please!!!

[stefy1066]

My son has a 1998 JGC. The check engine light is on and the scanner says "bad o2 sensor...bank one" The code is 123(?) i think. I know there are 2 sensors...one before the cat and one after.....which one is bank one???no one seems to know. The guy with the scanner said he's not sure but he thinks its the one in front......anyone???? I hate to replace the wrong one. He's only had the jeep a few weeks and its running a little rough....it hesitates sometimes on take off...but runs better after a few min. need to get a sticker soon and have to fix this problem before i do.... can anyone please give me an answer today? or any other thoughts??? thanks.

[Airjer_]

P0123 is a TPS code? knowing the exact code would help a lot!

Bank 1 refers to the O2 sensors on the side of the engine that cylinder #1 is located on. Bank 2 refers to the O2 sensors on the opposite side of bank 1. Sensor 1 refers to the O2 sensors in front of the cats. Sensor 2 Refers to the sensors after the cats.

So if the code was Bank 1 sensor 1 it would be the O2 sensor on the same side of the engine as cylinder #1 and it would be in front of the cat.

Just because it has a code for an O2 does not necessarily mean the O2 is bad!