Removal Procedure

WARNING: This page is about a different car, the 2002 Pontiac Bonneville. However, it is still accessible from the selected car via links, so may be relevant.

Replace the batteries when the range of the transmitter decreases to less than 7 m (23 ft).
Insert a small coin between the two halves of the transmitter case at the slot provided near the key ring hole.
Twist the coin in order to open the case.
Open the transmitter case.

Fig 1: Opening Transmitter Case
Courtesy of GENERAL MOTORS CORP.
Remove the battery (2).

Fig 2: Removing Battery
Courtesy of GENERAL MOTORS CORP.