Subaru Repair: check engine light, subaru forrester, gas milage

Question
I changed my o2 sensor in my 99 subaru forrester and the check engine light is still on.  Gas milage is much better.  Does this light need to be reset, and if so is there a reset switch?  Would you recommend changing the rear sensor also? I have not changed that just yet.  Thanks for your time.

Answer
The light may need to be turned off but if not it should go off after a few long drives at highway speed.  You must reset it with a scan tool, there is no reset switch.  If the light does not go off I would take it to a shop and have them check it out.  An O2 sensor code can be set because another part has failed. Like the converter, or the car running too rich, or too lean.  You may try just clearing the code first to see if anything else shows up.  Hope you get it fixed!