Sometimes O2 sensors don't go out all at once. Mine produced an intermittent CEL for a while until I replaced it. If you have a good idea of your typical fuel economy, keep an eye on that as that is another indicator of an O2 sensor going south. Pretty easy to replace. Either buy or get the loaner O2 socket. Break it loose with a breaker bar and it should be a 10 minute job.

 

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P0131 came back, so I guess I'm changing the sensor. "Bank 1 Sensor 1" is the upstream O2 sensor, correct?

Has anyone resolved this code any other way?

 

Funny, I have a new O2 sensor sitting on my workbench... Been driving the Miata though, and the wifey said the check engine light has stayed off for a few days now. I'll get it replaced soon...

 

Which code are you getting?

 

P0131. Funny I actually found some time last night to put it in. I was suprised how easy it came out (no PB Blaster).

My research on this forum found everyone with this code had it resolved by replacing the sensor. There were lots of people suggesting a few other items to change first, since the sensor is $70, but no evidence that there was any other reason people saw this code by itself.

 

P0131 and an inaccurate fuel gage points directly to the evap purge valve, have you had the recall done? I would do that first before shotgunning parts out of pocket. Can't post a link but google "focus evap purge recall"

 

The fuel gauge issue only happened once and I was able to put a few gallons in it the next day, so I suspect the gauge was accurate, but the hose just clicked off before filling the tank. I had the recall done a few months ago. No issues, so they just updated my PCM. I'd think a bad/failing evap hose should now (after the recall) throw a code. From everything I've seen, P0131 points to the upstream O2 sensor, so that's what I'm trying.

 

Just changed the O2 sensor, and the CEL was off the next time I started the car. Hope it stays off.

Advance Auto loans the sensor socket if anyone needs it. 110K+ miles on the original...