Chamberlain · Garage Door Opener Moderate

1-1 — Chamberlain 1-1 — Safety Sensors Obstructed/Misaligned/Disconnected

1-1 means the safety reversing sensors are obstructed, misaligned, disconnected, or have broken wiring (for more than ~4 seconds). It is a sensor fault, not a wall-control voltage problem. (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?
Yes, with caution
DIY difficulty
Easy
Typical cost
$25-40
Verified against
chamberlain.com ↗

The fix

Chamberlain/LiftMaster Safety Sensor Kit (041-0136, replaces 41A5034)

Safety reversing sensors obstructed, misaligned, or wired wrong

$25-40 easy difficulty 30 min Tools: screwdriver

Diagnose first: Chamberlain and LiftMaster share the same Security+ 2.0 sensor hardware and kit. Re-aim the sensors and clear the beam path first — that resolves most 1-1 faults for free.

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How to fix it

  1. Clear any obstruction and clean the sensor lenses.
  2. Realign both sensors until the indicator LEDs are steady.
  3. Check the sensor wiring and terminals at the opener.

Why it happens

Typical signs: Door will not close (reverses or will not move) · Sensor indicator LED off or flickering · Flash code 1-1

  • Safety sensors obstructed, misaligned, disconnected, or broken wire A blocked beam, knocked-out alignment, or a wiring break for more than ~4 seconds.

Other parts sometimes needed

If diagnosis points to a failed part, these are the common replacements. As an Amazon Associate we earn from qualifying purchases.

  • Garage door opener safety sensors Common replacement
    Amazon →

More Chamberlain garage door opener codes

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 2-1 2-1 — Logic Board Component Failure

All Chamberlain codes → All garage door opener codes →

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.