Instructions
Verify that there are batteries in your Sony PlayStation 3 remote. The remote does not have its own battery source -- you will need two AA-sized or four AAA-sized batteries, depending on the model, before syncing can take place.
Do not walk outside of the broadcasting range of your PlayStation 3. For best results, you need to stay within 30 feet of your console at all times while using the remote, or the remote will not be able to sync. If you have completed a sync with the remote and you walk outside of this broadcasting range, the two devices will stop communicating with one another.
Verify that the Bluetooth connectivity of your PlayStation 3 is switched "ON." The Sony PlayStation 3 and the PS3 remote sync together via the wireless Bluetooth technology. Enter the "Settings" menu on your PS3's main menu and select "Bluetooth" and "ON" to enable this connectivity. Try to sync your remote again.