Radio doesn't work

[FancyGirlinGB]

I'm new to the Celica GT world, and so happy to be here. I just purchased a 2001 GT, automatic, which for the past 3 years has been driven only occasionally, once or twice a month at most. One of the things my mechanic did was to replace the battery, and I'm wondering if Celicas need a "code" to make the radio work after battery replacement (already checked fuses). It's the stock Toyota radio from 2001. Thanks in advance!