2006 Lancer ES 55K, all scheduled maintenance

A couple of weeks ago my check engine light came on and I took it on in to the dealer. They said the O2 sensors were not communicating with the computer, so they reset it and the light went off. No charge for a reset, all was good.

For about 3 hours. Got back in the car that night, light came on. Right now I'm planning on going in this week, but I figured someone here might have run into this??

 

when you clear the codes they wont come back on until you start the car for the second time after they are cleared (if they are still present). the car has to run thru its cycle for it to notice that there is something wrong again.

 

mods?

 

we need more info. The code, mods, what's happened recently that could explain the issue, and so on.

 

All Stock

The Code was P0031
B1 Sensor 1

The car is running fine, no change in performance since the light has come on.

 

Change the o2 sensor that's in the exhaust manifold.