# Chamberlain code 4-6: the door won’t close because the sensors can’t see each other

Source page: https://garagedoorscience.com/code/chamberlain-error-codes/4-6

## The door won’t close because the sensors can’t see each other

The two safety sensors are out of line, or something blocked the beam between them for a moment.

**You can check this.** Line the sensors up until both of their lights glow steady, without flickering. Move anything that hangs in the doorway or sits on the door in the beam’s path.

From the maker’s manual:
- Chamberlain manual for model B980, PDF page 40: https://cgi.widen.net/content/vlzppckqt9/original/114a5126.pdf
- Chamberlain manual for models B4603T, B4643T, B4613T, B6713T, B6753T, PDF page 43: https://cgi.widen.net/content/zwq7paf7l4/original/114-5739-000.pdf

Garage Door Science isn’t affiliated with the opener makers LiftMaster, Chamberlain or Genie. Each meaning is our summary of the maker’s own manual, which we link.