Garage Door Openers

Blink codes, safety sensors, remotes and travel limits. Springs are refer-only.

5 field manuals · 62 error codes · 13 guides · 3 brands

Field service manuals

Manual · Garage Door Opener

Chain, belt and screw drive (trolley) garage door openers: field service manual

Ceiling-mounted rail openers with a trolley/carriage (chain, belt or screw drive), AC or DC motors, LiftMaster Security+ 2.0/myQ, Genie Intellicode, Overhead Door Odyssey/Destiny. Own summary; model families only.

7 components5 common failuresLiftMaster, Chamberlain, Craftsman, Genie, Overhead Door, Ryobi, Skylink
Manual · Garage Door Opener

Wall-mount (jackshaft) garage door openers: field service manual

LiftMaster wall-mount operators: 3800, 8500, RJO20/RJO20C (Learn-LED codes) and 8500W/RJO70, 98022/RJO101, 98032, LJ8900W/LJ8950W (arrow codes). Own summary.

5 components4 common failuresLiftMaster
Manual · Garage Door Opener

LiftMaster 87504 / Chamberlain B6765 & B4643T belt-drive openers (Security+ 2.0, myQ): quick sheet

Chamberlain Group belt-drive DC openers of the Security+ 2.0 / myQ era (post-2012 units with a round yellow LEARN button): LiftMaster 87504-267 Secure View (camera, battery backup) and Chamberlain B6765 / B4643T retail models. Confirm the code table on the label inside the light lens.

6 components3 common failuresLiftMaster, Chamberlain
Manual · Garage Door Opener

LiftMaster wall-mount jackshaft openers (8500W generation / 84505R): quick sheet

LiftMaster wall-mount (jackshaft) openers of the Wi-Fi / myQ era: 8500W, 8500WRGD, 8500WLA, LJ8900W, LJ8950W (codes published by Chamberlain), and the successor 84505R. Confirm codes on the unit label for the 84505R.

6 components2 common failuresLiftMaster
Manual · Garage Door Opener

Genie StealthDrive / SilentMax belt-drive openers (Aladdin Connect): quick sheet

Genie current belt-drive DC openers: StealthDrive 7055 / 7035 family and SilentMax 7155 (LED, Connect). One owner manual covers several current models. Confirm with the model label.

5 components2 common failuresGenie

Diagnostic guides · 12

Guide · Garage Door Opener

Door stops short or reverses at the floor (travel limits and force)

Usually travel limits or force need reprogramming, or the door is binding/out of balance. Test the door by hand first.

4 steps ~45 minmoderate
Guide · Garage Door Opener

Garage door reverses or will not close (safety sensors)

Nearly always the photo-eye safety sensors: blocked, misaligned, sun-blinded or miswired. Sensors must be repaired, never bypassed. If sensors are fine, look at force/limits and door binding.

5 steps ~30 mineasy
Guide · Garage Door Opener

Garage door won't move with the opener after the red release cord was pulled

The emergency release disconnects the door arm from the trolley. Re-engaging it is usually a matter of setting the release back to its connected position and running the opener so the trolley catches the carriage. First confirm the door is balanced; a heavy door means a spring problem, which is blocked work.

4 steps ~15 mineasy
Guide · Garage Door Opener

Garage opener light stays on, or will not light

A light that stays on is usually a feature (light button, motion detection, safety-light on beam break) or a door control/wiring fault; Chamberlain gives a test that separates the door control from the logic board. A dead light is usually the bulb, its type, or the socket.

4 steps ~30 mineasy
Guide · Garage Door Opener

myQ Wi-Fi opener offline or will not connect

myQ openers join only 2.4 GHz networks. Read the Wi-Fi LED, power-cycle opener and router, clear Wi-Fi and rerun setup in the app.

4 steps ~30 mineasy
Guide · Garage Door Opener

Noisy garage door opener

Loose fasteners, poor lubrication, slack chain, worn drive gear or an unbalanced door. Separate opener noise from door noise by running each alone.

4 steps ~40 mineasy
Guide · Garage Door Opener

Opener beeping (battery backup)

Beeps come from the battery backup: running on battery, low battery or a worn-out battery. Replace the 12 V battery when the LED is solid red.

3 steps ~20 mineasy
Guide · Garage Door Opener

Opener light or LED blinking

Blinks are diagnostic. Count the pattern and look it up by brand: LiftMaster arrows/Learn LED, Genie powerhead LED, Overhead Door round/long LED.

3 steps ~15 mineasy
Guide · Garage Door Opener

Opener runs or hums but the door does not move

Separate a disconnected trolley, a stripped gear/sprocket, a jammed trolley or a door problem (lock, broken spring). Door-side spring problems go to a door technician.

5 steps ~60 minmoderate
Guide · Garage Door Opener

Opener strains or door won't lift: broken spring (diagnose and refer)

Springs carry the door weight; the opener only guides it. A broken torsion or extension spring makes the door too heavy, and the opener strains, reverses or strips gears. Spring and cable work is blocked: confirm the symptom safely and refer to a garage-door technician.

4 steps ~15 mineasy
Guide · Garage Door Opener

Remote or keypad will not operate the opener

Check lock/vacation mode first, then the remote battery, then reprogram using the Learn/SET button. Short range is often radio interference from nearby LED bulbs.

4 steps ~20 mineasy
Guide · Garage Door Opener

Wall button not working (or door opens by itself)

A shorted or reversed wall-control wire is the usual cause, often from a staple. Phantom operation is commonly a shorted wall button or a stuck remote.

3 steps ~30 mineasy

Installation · 1

Install · Garage Door Opener

Garage door opener install (spring work BLOCKED)

An opener only moves a door that is already balanced by its springs. Check balance first, mount the rail and header bracket per the manual, place the safety reversing sensors no higher than 6 in above the floor and aligned, and test the auto-reverse. Spring and cable work is BLOCKED: refer to a garage door technician.

7 steps ~240 minmoderate

Genie · 15 codes

Genie · Garage Door Opener

Excelerator 1 blink

Motor drive board interrupt

Single source High-voltage / caution

Genie · Garage Door Opener

Excelerator 2 blinks

Controller board interrupt

Single source

Genie · Garage Door Opener

Excelerator 3 blinks

Overheated / over-cycled

Single source

Genie · Garage Door Opener

Excelerator 4 blinks

Force settings incorrect

Single source High-voltage / caution

Genie · Garage Door Opener

Excelerator 5 blinks

Safe-T-Beam fault

Single source

Genie · Garage Door Opener

Excelerator 6 blinks

Wall console fault

Single source

Genie · Garage Door Opener

Excelerator 7 blinks

Limit switch fault

Single source

Genie · Garage Door Opener

Excelerator 8 blinks

Wall console locked

Single source

Genie · Garage Door Opener

Green LED 1 blink, pause

Limits incomplete or path obstructed

Single source High-voltage / caution

Genie · Garage Door Opener

Green LED 2 blinks, pause

Safe-T-Beam problem or UP limit not set

Single source

Genie · Garage Door Opener

Green LED 3 blinks, pause

Limits set backwards

Single source

Genie · Garage Door Opener

Green LED 4 blinks, pause

Wall button wiring shorted or reversed

Single source

Genie · Garage Door Opener

Green LED 5 blinks, pause

Drive too tight or control failure

Single source

Genie · Garage Door Opener

Red LED 1 blink, pause

Remote not learned

Single source

Genie · Garage Door Opener

Red LED steady

Programming not finished

Single source

LiftMaster / Chamberlain / Craftsman · 39 codes

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

1-1

Safety sensors not seen (open circuit)

Cross-checked

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

1-2

Sensor wiring shorted or reversed

Cross-checked

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

1-3

Wall door control fault

Cross-checked

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

1-4

Sensors misaligned or briefly blocked

Cross-checked

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

1-5

No motor travel detected (RPM)

Cross-checked High-voltage / caution

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

1-6

Door moved on its own (coasting/drift)

Cross-checked High-voltage / caution

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

2-1

Logic board internal fault

Cross-checked

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

2-2

Logic board internal fault

Cross-checked

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

2-3

Logic board internal fault

Cross-checked

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

2-4

Logic board internal fault

Cross-checked

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

2-5

Logic board internal fault

Cross-checked

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

3-1

Operator moves slightly then stops

Cross-checked

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

3-3

Battery backup not charging

Cross-checked

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

3-5

Cable tension monitor fault

Cross-checked Licensed pro only

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

4-1

Too much resistance while closing

Cross-checked High-voltage / caution

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

4-2

Too much resistance while opening

Cross-checked High-voltage / caution

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

4-3

Lost motor travel signal while closing

Cross-checked

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

4-4

Lost motor travel signal while opening

Cross-checked High-voltage / caution

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

4-5

Travel module not recognized / communication error

Cross-checked

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

4-6

Sensors misaligned or briefly blocked

Cross-checked

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

5-5

Remote light required for unattended closing

Cross-checked

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

Battery LED flashing orange + beep every 30 s

Backup battery low

Cross-checked

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

Battery LED solid orange + beep every ~2 s

Running on battery

Single source

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

Battery LED solid red + beep every 30 s

Backup battery worn out

Cross-checked

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

Code 7

Motor short

Single source

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

Code 9

Cable tension reversal

Single source Licensed pro only

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

Code 10

Force reversal going up

Single source

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

Code 11

Maximum force reached going down

Single source High-voltage / caution

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

Code 12

Force reversal going down

Single source

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

Code 13

Maximum force reached going up

Single source High-voltage / caution

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

Code 15

Logic board memory error (CRC)

Single source

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

Learn LED 1 flash

Sensor wire open

Cross-checked

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

Learn LED 2 flashes

Sensor wire shorted or reversed

Cross-checked

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

Learn LED 3 flashes

Door control circuit fault

Cross-checked

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

Learn LED 4 flashes

Sensors misaligned

Cross-checked

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

Learn LED 5 flashes

No motor travel in the first second

Cross-checked High-voltage / caution

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

Learn LED 6 flashes

Motor circuit fault

Cross-checked

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

Lights flash 2 times (remote ignored)

LOCK mode on

Cross-checked

LiftMaster / Chamberlain / Craftsman · Garage Door Opener

Work lights flash ~10 times

Safety sensor problem

Cross-checked

Overhead Door · 8 codes

Overhead Door · Garage Door Opener

Long LED blue flashing, round LED off

Sure-Lock on (door will not open)

Single source

Overhead Door · Garage Door Opener

Long LED red flashing, round LED off

Door contact or door component problem

Single source High-voltage / caution

Overhead Door · Garage Door Opener

Long LED red steady, round LED off

Thermal cutout

Single source

Overhead Door · Garage Door Opener

Round + long LED purple flashing

Radio receiver error

Single source

Overhead Door · Garage Door Opener

Round + long LED red flashing

Program error or component failure

Single source

Overhead Door · Garage Door Opener

Round + long LED red steady

Limits not set

Single source

Overhead Door · Garage Door Opener

Round LED blue or purple flashing

Remote not programmed

Single source

Overhead Door · Garage Door Opener

Round LED red flashing, long LED off

Safe-T-Beam blocked or interference

Single source

Official manufacturer support

We link to official documentation and never host it.

LiftMaster / Chamberlain / CraftsmanChamberlain Group support (LiftMaster, Chamberlain, Craftsman openers)LiftMaster / Chamberlain / CraftsmanWhich diagnostic chart applies to your openerLiftMasterLiftMaster websiteChamberlainChamberlain websiteGenieGenie opener troubleshootingOverhead DoorOverhead Door websiteRyobiRyobi garage door opener installation troubleshootingSkylinkSkylink website