!!
critical Chamberlain
Error Code Battery Status LED solid red
12V battery needs to be replaced. Beep sounds every 30 seconds.
? What Causes This
12V battery will no longer hold a charge and needs replacement.
✓ How to Fix It
Replace the 12V battery with Chamberlain part# 41A6357-1 to restore battery backup functionality.
Source: page 38 of the official manual
From the manual
This error code appears in:
Chamberlain Chamberlain Garage Door Opener