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  • avatar MrShift@Edmunds 04/20/10 2:10 pm PST

    Well your problem could be whoever is fixing the car. Just because you get an O2 error code does not mean the 02 sensor is bad. All this tells you is that the 02 sensor isn't happy for some reason---that the 02 circuit is not up to specs. If the lights go on and off this generally means the problem is intermittent.

    You need to take it to someone who does diagnostics, not just parts replacement. If you had the transmission trouble code # and the 02 sensor # code, we might be able to give you more info.

    You may respond to this thread by clicking on "Answer This Question" below

Answers

  • MrShift@Edmunds 04/20/10 2:10 pm PST

    Well your problem could be whoever is fixing the car. Just because you get an O2 error code does not mean the 02 sensor is bad. All this tells you is that the 02 sensor isn't happy for some reason---that the 02 circuit is not up to specs. If the lights go on and off this generally means the problem is intermittent.

    You need to take it to someone who does diagnostics, not just parts replacement. If you had the transmission trouble code # and the 02 sensor # code, we might be able to give you more info.

    You may respond to this thread by clicking on "Answer This Question" below

  • kim1974 04/20/10 4:51 pm PST

    Both times I received the code PO157 for the O2 sensor and the second time the check engine light came on I also received the transmission code of U0404 and the code PO157 for the O2 sensor. I had the dealer look at the vehicle the first time one week after I purchased it and 3 days after it happened the first time and I paid for them to run diagnostic testing and the only thing they found was a bad O2 sensor. They charged me for the diagnostics and to replace the O2 sensor and it went back off again in less than 24 hours. Everytime this was looked at it was at the dealer's garage. This was a big dealership in Fond du Lac where I purchased this vehicle. I also then took it to a transmission specialist where the dealer set up an appointment for me and they said they didn't see anything wrong with the transmission and re-set the check engine light. It went back off that afternoon. I then had the dealer come and pick up the vehicle and they kept it for over a week. It had the second O2 sensor replaced and my sales person drove the Jeep and the check engine light didn't come on for them. When I got it back it came on for me but by then my 1 month/1000 mile warranty was up and the dealer no longer wanted to help me with this problem. If I can't find the problem I'm ready to trade this vehicle in for something else and I've only had it for 3 months. I don't like the constant worry of the check engine light coming on and off.

  • MrShift@Edmunds 04/20/10 8:00 pm PST

    Hold on. If they failed to fix it while it was in warranty, then they still owe you a fix, if the code is the same one as they "fixed". A trip to Small Claims Court might settle this argument.

    But aside from all that, what you need is someone *competent* to diagnose this problem. There is a diagnostic tree of step by step instructions on how to debug this code, all the way from testing the 02 voltages, to checking for loose, corroded or shorted wiring to replacing the PCM module.

    Code UO404 is addressed by a NAG 1 Transmission Verification Test

    These are not necessarily easy problems to track down, so you'd best insist on your warranty. You can't bail out of a broken car, you'll get creamed on the resale. It's time to dig in your heels and demand satisfaction or go to Small Claims if they refuse--my opinion is that they didn't fix the problem during warranty.

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