2001 chev prizm CEL code

My car’s Check Engine light decided to come on, so I hooked up my CarChip to check the diagnostic codes. It threw me a P0133 - O2 sensor circuit slow response. A couple of questions: What causes such a code to occur, and how is it fixed? I’ve reset it for the time being, and the CEL hasn’t come back on, but earlier in the week I reset it and it came back on after driving it a while (probably after 60-100 mi). Don’t know if that matters, but whatever. Thanks in advance.

Check this out: http://www.obd-codes.com/p0133

I have always found that site, in general, to be very useful.

Thanks for the link, very helpful. Pretty sure it’s the o2 sensor then, as I had an issue with a dirty MAF sensor last year that was giving me issues, so I’m pretty sure that’s whats going on.