Code P0031

[djb383]

CEL just now went steady on, ScanGauge shows P0031, clear code, CEL back on steady in a few seconds with P0031 again. Any updates about the O2 sensor and/or ECU since Nov '11? '05 base, automatic, 63K, flawless for 7 years, owned since new.

[dgekiere]

I remember being in the dealership working on a base vibeand having that code. I found a broken wire to the o2 sensor right at the dealership sensor it self. It was the sensor right inder the pasenger side floor board. Otherwise to check it you can take an ohm meter and measure the resistance of the o2 heater circuit. For the code to come back that quick i am guessing its time for an o2 sensor

[djb383]

Everything I've read says P0031 is bank 1 sensor 1, or the upstream A/F ratio sensor. I got the old OE sensor out (amazing how easy that was), in order to get the correct replacement O2 part number, and naturally it must be ordered.

My plan is to remove the - battery cable 1st (to clear the code) and then remove the old O2 and replace with the new O2. Am I missing anything, any suggestions? Hopefully at start-up the CEL is out and will stay out.....state inspection is due end of July.

[djb383]

FWIW update, installed a new Denso (original type) upstream O2 sensor ($150 from Advance Auto Parts , connector matched perfect), cleared the code with the ScanGauge and no more CEL, case closed.

[trb]

Good job! Have you gotten the inspection yet? If you haven't, the car will have to be driven a while and through several drive cycles to reset the computer to all "ready" codes or it will fail the inspection. Seeing as it is the end of the month, you still have the 7 day grace period to get it done next month. I actually always get it done the next month. It has saved me 2 yearly inspection fees on my Mustang as I get at least 13 months on each sticker!

[djb383]

Negative, the ScanGauge clears any/all codes, codes stay cleared if problem solved, inspection passed yesterday, no problems.

[trb]

That's great, but I was not talking about the problem codes, but the ready codes. On the cars I've worked on before, if you remove the battery cable like you mentioned in your earlier post, you do have to drive a certain number of cycles to fully reset all of the sensors. But if you didn't pull the cable to clear the codes and just used the Scangauge, then the other sensors were still OK. I wasn't sure if you did pull the cable or not, just figured I'd mention it and save you some hassle. So you are good for another year now!

[djb383]

I forgot to disconnect the battery before I started the O2 replacement. After O2 replacement, CEL was on just turning the key to on, start the motor and CEL was still on. Scan for codes again and ScanGauge still displays P0031. Select "clear codes" and bingo, no more CEL, scan for codes again and display says "no codes found". All's good in my universe again. If that's all that goes wrong with our Vibe every 7 years, then I think GM (with 'yota's help) may have a winner. Thanks for the info.