Garage door opener light blinking: what LiftMaster, Chamberlain and Genie codes mean

36 blink codes from the makers’ own help sites. LiftMaster or Chamberlain with arrows: count UP flashes, then DOWN — 1 UP, 1 DOWN (code 1-1) is a blocked or misaligned safety sensor. Genie: 5 green blinks is a Safe-T-Beam fault on an Excelerator but a too-tight chain on a ChainLift 800. Pick the maker, the light and the count.

Find it by what you see

36 codes.

LiftMaster Code 1-1: 1 UP flash, 1 DOWN flashOne of the safety sensors is blocked, out of line or unplugged, or its wire is broken.
LiftMaster Code 1-2: 1 UP flash, 2 DOWN flashesThe safety sensor wiring is probably reversed or shorted, so the door will not close.
LiftMaster Code 1-5: 1 UP flash, 5 DOWN flashesThe opener did not sense the motor turning just after a command, so it hums or clicks and the door barely moves or does not move.
LiftMaster Code 1-6: 1 UP flash, 6 DOWN flashesThe opener sensed door movement it did not start, usually because the door is out of balance, or because a door on a jackshaft opener was moved by hand with the emergency release disconnected.
LiftMaster Codes 2-1 to 2-5: 2 UP flashes, 1 to 5 DOWN flashesThe opener detected a possible fault in an electronic component on its logic board, and does not respond to commands at all.
LiftMaster Code 3-5: 3 UP flashes, 5 DOWN flashesOn the wall-mounted jackshaft models, the cable tension monitor sensed slack in a door cable, which LiftMaster treats as a safety hazard.
LiftMaster Code 4-1: 4 UP flashes, 1 DOWN flashResistance while closing: the opener sensed an unexpected change in motor speed on the way down, so the door reverses, stops or struggles at any point while closing, not only near the floor.
LiftMaster Code 4-2: 4 UP flashes, 2 DOWN flashesResistance while opening: the door stops before it is fully open.
LiftMaster Code 4-3: 4 UP flashes, 3 DOWN flashesMotor speed lost while closing: the motor slowed unexpectedly, and the door stops and reverses just before it touches the floor.
LiftMaster Code 4-4: 4 UP flashes, 4 DOWN flashesMotor speed lost while opening: the motor slowed unexpectedly and the door stops before it is fully open.
LiftMaster Code 4-5: 4 UP flashes, 5 DOWN flashesThe opener does not recognise the travel module installed in it, usually right after a part was replaced, and the door will not move.
LiftMaster Code 5-5: 5 UP flashes, 5 DOWN flashesOn the wall-mounted jackshaft models, the door ignores the myQ app and schedules (the wall control and remotes still work) because a myQ-compatible light must be installed and paired before the opener will move the door unattended.
LiftMaster Learn button LED flashes onceA safety-sensor problem that stops the door closing: a sensor wire is broken or disconnected.
LiftMaster Learn button LED flashes 2 timesA safety-sensor problem that stops the door closing: a sensor wire is shorted, or the black and white wires are reversed.
LiftMaster Learn button LED flashes 3 timesA door control fault: the light or screen on the wall-mounted door control is not lit.
LiftMaster Learn button LED flashes 4 timesThe sensors are out of line: the sending sensor works but the receiving sensor’s light is dim or flashing.
LiftMaster Learn button LED flashes 5 timesThe opener sensed no motor rotation in the first second of a run, which LiftMaster says is usually a mechanical obstruction.
LiftMaster Learn button LED flashes 6 timesA motor circuit fault.
LiftMaster Opener lights flash 10 timesThe opener’s own lights flash 10 times and the door will not close: the safety reversing sensors have a problem.
LiftMaster Opener lights flash 2 timesThe LOCK feature on the wall door control is on, so the door does not respond as normal.
Genie Excelerator: green LED blinks once, repeatingMotor drive board interrupt.
Genie Excelerator: green LED blinks 2 times, repeatingController board interrupt.
Genie Excelerator: green LED blinks 3 times, repeatingThe opener has overheated or has been run too many times in a row.
Genie Excelerator: green LED blinks 4 times, repeatingThe force settings are incorrect.
Genie Excelerator: green LED blinks 5 times, repeatingSafe-T-Beam malfunction.
Genie Excelerator: green LED blinks 6 times, repeatingThe wall console does not work.
Genie Excelerator: green LED blinks 7 times, repeatingThe limit switches are not working.
Genie Excelerator: green LED blinks 8 times, repeatingThe wall console is locked (the vacation lock is on).
Genie 600/700/800 series: red LED on steadySetup is not complete.
Genie 600/700/800 series: red LED blinks once, pause, repeatA remote is not programmed to the opener.
Genie 600/700/800 series: green LED blinks once, pause, repeatThe limits are not fully programmed, or the Safe-T-Beam was blocked or the door met an obstruction on the way down.
Genie 600/700/800 series: green LED blinks 2 times, pause, repeatThe UP limit is not set, the powerhead wiring has failed, or the Safe-T-Beams are out of line or continuously blocked.
Genie 600/700/800 series: green LED blinks 3 times, pause, repeatThe limits were programmed in the wrong order.
Genie 600/700/800 series: green LED blinks 4 times, pause, repeatThe wall button’s wire is shorted or its connections are reversed.
Genie 600/700/800 series: green LED blinks 5 times, pause, repeatThe chain or belt is too tight, or the control system has a fault.
Genie Safe-T-Beam sensor: red light blinkingA Safe-T-Beam malfunction has occurred.

LiftMaster and Chamberlain do not name the colour of the arrows, the Learn button LED or the bulbs, so those codes match any colour you pick. A light the maker says is blinking without a count (Genie’s red Safe-T-Beam light) matches any count.

By maker

What these pages cannot do

They give no repair instructions of their own. Each code page repeats only the maker’s steps, and each carries the maker’s own safety line: garage door springs and cables are under extreme tension, and the makers say to leave them to a professional or trained door technician.
They never tell you to work around a safety sensor. 8 of these codes are about the safety sensors (photo eyes); on those pages only the maker’s alignment and cleaning steps are repeated.
They cannot tell two series apart by the count. Read the model on the label on the motor unit: Genie’s Excelerator and its 600/700/800 models give the same counts different meanings.
A wall control has no blink code of its own on the makers’ pages we read; a wall control fault shows on the opener head instead (the LiftMaster Learn button LED flashing 3 times, a Genie Excelerator blinking 6 times).

Left out, and why

A maker gets pages when its own site documents at least 5 opener codes and we could read them. LiftMaster (with Chamberlain) and Genie did. These were not used:

liftmaster.com and chamberlain.com help pages — Both brands’ own support links (www.liftmaster.com/support and www.chamberlain.com/support) answer HTTP 301 and redirect to support.chamberlaingroup.com, the parent company’s shared help site. That shared site is the source used for both brands, with Chamberlain named alongside LiftMaster on every page. www.liftmaster.com Checked 2026-09-29.
Craftsman — Craftsman’s own help site refused our fetch (HTTP 403). What its search surfaces for openers is remote and keypad answers, not a table of at least 5 flash codes, so there is no Craftsman page. support.craftsman.com Checked 2026-09-29.
Linear (Nice/Linear) — The LDCO841/863 installation manual answered (HTTP 200), but it is a 2.3 MB PDF whose flash table we could not extract reliably in this pass. Nothing from it is guessed, so there is no Linear page yet. www.linearproaccess.com Checked 2026-09-29.
Marantec — Marantec America’s FAQ answered (HTTP 200), but it mentions lights only inside single answers (a blinking red photo-eye LED means the eyes are out of alignment; LEDs used for installer fault-finding), not a table of at least 5 codes an owner reads. marantecamerica.com Checked 2026-09-29.
Hörmann — The ProMatic 4 manual link on Hörmann UK answers HTTP 302 and hands the file over from asset-center.com, a host that is not Hörmann’s own domain, so under the own-domain rule it was not used. www.hormann.co.uk Checked 2026-09-29.

Sources

Each maker’s own help pages only, read on the date shown.

LiftMaster and Chamberlain

Chamberlain Group Support (LiftMaster and Chamberlain): Garage Door Opener | Diagnostic Codes and UP/DOWN Flashing Lights — LiftMaster and Chamberlain Security+ 2.0 and Security+ 3.0 openers with UP and DOWN arrows; codes 3-5 and 5-5 only on the wall-mounted jackshaft models 8500W/RJO70, 98022/RJO101 and 98032. support.chamberlaingroup.com Checked 2026-09-29.
Chamberlain Group Support (LiftMaster and Chamberlain): What Does the Flashing LED Next to the Learn Button Mean — LiftMaster and Chamberlain openers without UP and DOWN arrows, which flash the LED beside the Learn button. support.chamberlaingroup.com Checked 2026-09-29.
Chamberlain Group Support (LiftMaster and Chamberlain): Garage Door Opener Light Blinks but The Door Won’t Close — LiftMaster and Chamberlain openers with safety reversing sensors and a door control with a LOCK button. support.chamberlaingroup.com Checked 2026-09-29.

Genie

The Genie Company: Genie Excelerator® Series Garage Door Opener Self-Diagnostic Troubleshooting — Excelerator series: H8000, H8000-07, H8000D, ISD990, ISD995, ISD1000, PRO99, PRO99-21C, PRO99FN, CMD9900. store.geniecompany.com Checked 2026-09-29.
The Genie Company: Genie Garage Door Opener Troubleshooting Guide- for models 1022, 1024, 1042, 2022, 2024, 2042, 2027 — ChainLift 600 (1022), ReliaG 600 (1024), BeltLift 600 (1042), ChainLift 800 (2022), ReliaG 800 (2024), ChainLift 700 (2027), QuietLift 800 (2042). store.geniecompany.com Checked 2026-09-29.
The Genie Company: Why is the red Safe-T-Beam® light blinking? — Genie openers with Safe-T-Beam sensors (the page names no model). support.geniecompany.com Checked 2026-09-29.