The Auto-On feature only works for Optical and LG Wireless Sound Sync from your TV, or with Bluetooth devices that have already been paired.
Make sure your speaker is turned on.
Press the Auto Power On button on your remote.
Your speaker will automatically turn itself back off when you are done using it. If you turn your soundbar off with the Power button, this feature will be disabled, and Auto-On will have to be enabled again.
6. What's next?
7. Manually Pair Subwoofer
Your subwoofer must be within 30 feet of your soundbar for it to work.
Turn off your soundbar.
Using a bent paperclip or a pen, push the pair button on the back of your subwoofer.