And before all of you owners manual fanatics go off yes it's on page 25 there too.
Transmitter Battery Replacement
The recommended replacement battery is CR2032.
Perchlorate Material – special handling may
apply. See Managing Hazardous Waste perchlorate 1. If the RKE transmitter is equipped with a screw, remove the screw. With the RKE ransmitter buttons facing down, use a flat blade to pry the two halves of the RKE transmitter apart. Make sure not to damage the elastomer seal during removal. 2. Remove and replace the battery. When replacing the battery, match the + sign on the battery to the + sign on the inside of the battery clip, located on the back cover. Avoid touching the new battery with your fingers. Skin oils may cause battery deterioration. If you touch a battery, clean it with rubbing alcohol. 3. To reassemble the RKE transmitter case, snap the two halves of the case together. Make sure there is an even “gap” between the two halves. If equipped, install and
tighten the screw until snug. Test RKE transmitter
Some people here love telling people to read the manual