More O2 sensor problems...

I had a new cat-back system put on and when I got home from the muffler shop my check engine light came on. So I went to Adavance and use their OBD-II scanner and it came up with one code.

P0138
O2 sensor circuit hight voltz (bank 1 sensor 2)

I was told by both Advance and my jeep dealer that it was the upstream O2 sensor, so I replaced it yesterday, and disconnected the battery to reset everything. Then after I drove around a bit the light came on again

So today I went and used the scanner again and the same stupid code came up. The guy at Advance wasn't sure what the heck was up. Then I went to the Jeep dealer and the service guy was super nice and helpful. He reccomended that I try replacing the sensor after the cat and then he told me to disconnect the battery for 15 minutes or so, take off the intake tube, and hold the throttle open with my fingers for a few minutes. I guess that recalibrates everything completely...


What do you guys think?
Any suggestions at all would be great

You should be able to clear the codes on OBD-II with a good scanner - since you've changed that sensor, you'll need to force a reset of the system and then give it a chance to generate the new code, if it's there.

Keep this in mind anytime you change a part due to a code on OBD-II - and you might want to get yourself a scanner for your own use. AutoXray makes a decent unit (I have one of their OBD scanners) and it should give you all the functions you need, read your codes, and be able to force the reset after you fix things.

For anyone with OBD &/or OBD-II vheicles, I would suggest getting your own scanner. You're going to get enough use out of it to make it worth spending the money, and you should have no trouble at all finding one for well under $200 - and under $100 is a possibility...

5-90

should I replace my downsteam 02 sensor anyways?

and does disconnecting the battery and draining that system not completely reset the computer?

O2 sensor circuit hight voltz (bank 1 sensor 2)

Click to expand...

JCWarrior, number 2 sensor is the downstream sensor. Number 1 would be the one closest to the manifold, and number 2 would be the next in line. I think you might have replaced the wrong sensor......?

And as you probably know, everything is "bank 1" on an inline engine (there is no bank 2).

I'd take a close look at the O2 wiring though, since the exhaust was worked on. Someone may have simply left the sensor disconnected, or damaged it somehow.