Chamberlain · Garage Door Opener Serious
4-3 — Chamberlain 4-3 — Loss of RPM While Closing
4-3 means a loss of power/RPM in the motor while closing (loss of RPM during DOWN travel). It is not an unprogrammed-travel-limits condition. (Diagnostic meaning corrected against the official Chamberlain Group / LiftMaster Security+ 2.0 chart; flash-code meanings can vary by opener family — confirm for your exact model.)
- Keep using it?
- Limited use only
- DIY difficulty
- Moderate
- Verified against
- chamberlain.com ↗
How to fix it
- Check for binding by moving the door by hand with the opener released.
- Inspect the motor and RPM sensor; service if it persists.
Why it happens
Typical signs: Door stops while closing · Flash code 4-3
- Loss of motor RPM during down (close) travel The motor lost speed/feedback while closing — binding or a motor/RPM issue.
More Chamberlain garage door opener codes
1-1 1-1 — Safety Sensors Obstructed/Misaligned/Disconnected 1-2 1-2 — Safety Sensor Wires Shorted or Reversed 1-3 1-3 — Door control wire issue / lock button stuck 1-4 1-4 — Safety sensors misaligned or obstructed 1-5 1-5 — Motor Drive / No RPM at Start of Movement 1-6 1-6 — Unexpected RPM After Stop at Open Position
Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician. Verified against manufacturer documentation: chamberlain.com.