Diagnosis
The wireless connection between the soundbar and subwoofer is lost. This happens after a power surge, moving the units, or interference from other wireless devices.
How to Fix It
Re-pair the subwoofer. Unplug both the soundbar and subwoofer from power. Plug the soundbar back in. Then, plug the subwoofer into a power outlet. The pairing should happen automatically within 30 seconds. You'll hear a low thump from the sub.
If That Didn't Work
Check the subwoofer's status LED. If it's blinking, press the ID SET button on the back of the subwoofer for 3 seconds. Then press and hold the 'Up' button on the soundbar remote for 5 seconds to force a search.
Heads Up
Keep the subwoofer within 30 feet of the soundbar with a clear line of sight. Thick walls, metal furniture, or Wi-Fi routers can block the 5.8GHz wireless signal.