I have a Pontiac SV6 mini van. I found the remote control sometimes not work. I try to replace the battery of it.
The number on the back of remote control is GM/L:15100811.
The front looks like below.
The battery type is CR2032. Very popular, you can find it in any stores.
The steps to replace the battery in a Pontiac Remote Control
1) Insert a small knife or thin flat-head screwdriver between the remote halves, directly underneath the slot for your key ring. It is actually the part I circled it in red above.