My check engine light was on last week. It was throwing out a gas cap code, a misfire code, and an EVAP code.

I pulled the battery and reconnected. Check engine light is out. Are these codes still in the computer?

 

Did you check anything else, or just reset?

 

I just pulled the neg terminal for 10 min.. Reattached and started jeep. Light is off.

Just curious to see if the codes are still in memory

 

Did you check what causes the codes?

 

Gas cap is fine. I think I need an O2 sensor and not sure about the misfire. I will have a mechanic look at it.

I will ask a 3rd time. Do these codes stay in the computer after I reset?

 

Not really. Monitored systems, like the EVAP system and Misfire will come back (CEL on) after two trips if the condition(s) still exist. If you have a scanner, you may find them as Pending DTC's even though the CEL is not on (yet).

Why do you think you need an O2S?

Can you post the actual DTC Codes?