1996xj

okay my check engine light has been on for awhile i got off school today and me and some jeep buds went to advanced auto parts. and i had my check engine light tested and it came up as a bad heated oxygen sensor bank sensor 2 so it says my oxygen sensor is defective where is this thing at on my jeep.. and should i replace it. my friends also said it could cause bad gas mileage is that true help please

Abovetimberline

Sensor two is located on the outlet of your cat,it can cause bad gas mileage,the 02 sensor on the outlet is to monitor efficency of the cat.

1996xj

and how much of a change will i see in gas mileage

Abovetimberline

The 02 sensor monitors the cat to make sure it is doing its job,if it is not working it will not be able to manipulate the sensor in front of the cat which controls the injectors.just because you have an engine light does not always mean your sensor is bad,it means it is out of its voltage range,an engine misfire can cause 02 sensors codes. If your engine starts to run rich due to a bad sensor it will cause damage to your cat due to the increase in unburnt fuel. I would have it tested,or test it yourself. And replace if needed.

1996xj

thanks for the help it is indeed in the problem but my dad wants to wait to ask my brother seeing as it was his jeep before mine so i have to wait till he gets off work to see if he has replaced it or not... i crawled under and looked at it and by the looks of her it hasn't been

fafafofi

Check your 20amp fuse under the hood. A couple of us were going through the same thing and spent a bunch of money on unneeded sensors. Not saying this could be your prob, but you might as well check the cheapest fix first.