95 Tercel Check Engine light

Ok, so I get back from my 4-month deployment and have a dead battery. I get a new one, change it, the car starts up right away and runs fine, but the check engine light has been on ever since. A guy I work with said that happened to him to when he changed the battery in his Toyota truck and said he had to go to the dealer and have them reset it. Is this a Toyota thing that the check engine light comes on when you diconnect power?

There might be something wrong with the car. Have it check becuase it might not passed the smog.

I took it to Auto Zone today for their free Check Engine test. They hooked up the code thing and it said something about EGR flow something something. But, when they disconnected the meter, the light went out! Maybe it just needed a little jolt.