The Magna Headlamp FAQ:

[Red Valdez]

My concern is the last time I replaced the battery myself, I left in disconnected too long and the engine management computer re-set itself and had to go to Mitsi's to get it set up again along with a throttle body clean, which I want to avoid doing again.

You can perform the learning procedure yourself. The guide is here.

Otherwise, your automatic transmission will resume usual shifting after a week or two's worth of driving. You'll get an ocassional flared gear change but nothing to worry about.

At the end of the day though there's no need to go back to the dealer for it.

[rakhurst]

I've got the 5 speed manual trans in mine. The problem I had after the battery disconnect, was engine simple wouldn't idle. Drove it to work and back (hour each way in heavy traffic) next day and went nearly insane where it would stall nearly every time I had to stop. Never did get the hang of heal and toe manoeuvre

I guess if I persisted and drove it for long enough, it would self learn.