2GIG Smoke Dectector low battery despite battery change

I received a warming for my 2gig Smoke/CO2 detector having low batteries. I replaced them with 2 brand new 3V Lithium cell yet my low battery alarm persists. I tried holding the TEST button on the smoke alarm without any success. Any advice for resetting this alarm? Thanks

Just replacing the batteries should be enough to do it. What model number is your smoke detector? What light color/pattern is flashing on it?

It may help to remove the batteries, leave them out for at least 30 seconds, and put them back in again.