Garage door opener error codes and blink patterns
Source-backed Linear, Marantec, Craftsman, LiftMaster, Chamberlain and Genie error-code, arrow-flash, lamp-flash and LED-pattern troubleshooting organized by the signal your opener actually shows.
Read the exact manufacturer signal before changing settings. A Craftsman 4-UP/6-DOWN code, a Chamberlain Group diagnostic pair, a Genie Safe-T-Beam pattern and a powerhead LED pattern are different diagnostic languages even when the visible door symptom looks similar.
Start with the code, blink count or LED location—not the generic symptom. Garage Opener Help keeps manufacturer signal systems separate and then maps them into broader failure families only after the original evidence is preserved.
If the opener gives a repeatable code, that signal should normally outrank a broad symptom checklist. Record the model, the direction of travel and what the door did at the moment the code appeared before resetting power or relearning travel.
What to capture before changing anything
- Confirm where the signal appears: adjustment arrows, powerhead LED, sensor LEDs or app.
- Count the full repeating pattern before power-cycling.
- Keep UP/DOWN direction and blink pauses exactly as observed.
- Use model/generation notes before applying a code table from another opener family.
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Search by code, blink count, LED state or manufacturer signal.
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Codes & blink patterns
LiftMaster Error Code 4-1: RPM / Current Change During Closing
What the 4-1 code means, what you can safely check, and when the problem points beyond a simple setting.
LiftMaster Error Code 1-2: Safety Sensor Wiring Issue
A focused checklist for a 1-2 code: wiring, bare copper, sensor status and the next safe step.
Garage Door Opener Lights Flash 10 Times and the Door Won’t Close
On many Chamberlain/LiftMaster units this points to the safety-reversing sensor circuit. Here is how to narrow it down without guessing.
Genie Safe-T-Beam Red Light Blinking: What It Means
A blinking red Safe-T-Beam LED indicates a malfunction. Start with the beam path, lens alignment and wiring.
Genie Safe-T-Beam 2 Blinks: Alignment, Obstruction or Sensor Fault
The two-blink pattern means different things depending on the companion LED. Read both sides before replacing a sensor.
LiftMaster Error Code 4-2: Excessive Opening Force Detected
What 4-2 means when the door stops before fully opening, and how to separate binding door hardware from an opener travel issue.
LiftMaster Error Code 4-3: Motor Power Loss Detected
Why a 4-3 code points away from simple sensor alignment and toward the motor/travel-module path.
LiftMaster Error Code 4-5: Unrecognized Travel Module
A 4-5 is not a normal limit-adjustment message. It means the operator does not recognize the installed travel module.
LiftMaster Error Code 4-6: Safety Sensors Obstructed or Misaligned
Use the two sensor LEDs and the beam path to diagnose a 4-6 closing fault before replacing parts.
Genie Safe-T-Beam 3 Blinks: Sensor Interference
When the red source LED blinks three times and the green sensor LED stays on, Genie points to interference at the receiving sensor.
Genie Safe-T-Beam 4 Blinks: Source Not Sending Pulses
Four red blinks with the green LED on is a different branch from alignment or interference: Genie points to the source/transmitter itself.
LiftMaster Error Code 1-1: Safety Sensors Blocked, Misaligned or Disconnected
Code 1-1 is a safety-sensor circuit fault, but the fix depends on whether the beam is blocked, alignment is lost, or wiring is open.
Chamberlain Garage Door Sensor Green Light Blinking
A blinking green receiving LED points first to misalignment or obstruction; use the beam path and bracket position before replacing sensors.
How to Program a Genie GL2T Two-Button Flashlight Remote
Use the GL2T's documented 30-second pairing window and match the opener's Program-button or Learn-Code generation before pressing the remote.
LiftMaster Error Code 1-3: Wall Control Wire Short
Code 1-3 is a control-wire diagnosis, not a remote-radio problem: the remotes can work while the wall control stays dead.
LiftMaster Error Code 1-5: No RPM Detected at Startup
Code 1-5 is broader than a single failed travel module. Start by recording exactly what the motor and door do in the first few seconds.
LiftMaster Error Code 3-5: Cable Tension Monitor Tripped or Missing
A 3-5 code belongs to the jackshaft/wall-mount cable-tension-monitor branch, not to ordinary trolley-opener safety sensors.
LiftMaster Error Code 4-4: Loss of RPM During Opening
Code 4-4 is an UP-travel RPM loss. It is not a safety-sensor obstruction code.
LiftMaster Error Code 5-5: Unattended myQ Command Needs the Remote Light
A 5-5 code can be a missing/programming requirement for the myQ Remote LED Light on systems that require it for unattended operation.
LiftMaster Error Code 1-4: Brief Sensor Obstruction or Misalignment
Code 1-4 records a safety-sensor interruption that lasted less than four seconds, so the useful question is whether the beam was briefly crossed or the receiver is only marginally aligned.
LiftMaster Error Code 1-6: RPM Detected After the Motor Stops
Code 1-6 is about unexpected movement/feedback after the opener reaches the open position, not a photo-eye fault.
LiftMaster Error Codes 2-1 Through 2-5: Logic Board Failure Family
Codes 2-1, 2-2, 2-3, 2-4 and 2-5 are grouped by Chamberlain Group as logic-board component failures rather than five unrelated homeowner adjustments.
LiftMaster Error Code 3-2: Power Loss and Travel-Position Recovery
Code 3-2 is a power-loss recovery state: the opener needs to re-establish where it is in travel after power returns.
LiftMaster Error Code 3-3: Logic Board / Battery Over-Voltage Condition
Code 3-3 is an electronics branch; the detailed table links it to a logic-board component failure with battery over-voltage detected.
Genie Powerhead Red LED Solid: Programming Is Incomplete
On specific Genie 1022/1024/1042/2022/2024/2042/2027 openers, a continuously lit red diagnostic LED means required setup is not complete.
Genie Red LED 1 Blink: Transmitter Has Not Learned
A repeating one-red-blink powerhead pattern on specific Genie opener families points to a transmitter that has not been learned into receiver memory.
Genie Green LED 3 Blinks: Travel Limits Are Set Backwards
On the documented Genie 1022/1024/1042/2022/2024/2042/2027 family, three repeating green powerhead blinks mean the travel limits were programmed in the wrong direction.
Genie Green LED 4 Blinks: Wall Button Wire Short or Reversed
Four repeating green powerhead blinks on the documented Genie family point to the wired wall-control circuit, not a handheld remote or Safe-T-Beam fault.
Genie Green LED 5 Blinks: Chain/Belt Too Tight or Control-System Failure
Five repeating green powerhead blinks on the specified Genie family are a two-branch diagnostic: excessive chain/belt tension or a control-system failure.
Genie Excelerator 4 Blinks: Force Settings Incorrect
On the Excelerator screw-drive family, four repeating status-light blinks point to force settings that need attention—but Genie also tells you to check the garage door condition before treating this as a settings-only problem.
Genie Excelerator 5 Blinks: Safe-T-Beam Malfunction
Five repeating Excelerator status-light blinks point to the Safe-T-Beam system. The next step is to read the sensor LEDs—not to assume the opener control board has failed.
Genie Excelerator 6 Blinks: Wall Console Does Not Work
Six repeating Excelerator status-light blinks point to the wired wall-console path. Genie tells owners to inspect the low-voltage wall-console wiring and connections before replacing unrelated opener parts.
Genie Excelerator 7 Blinks: Limit Switches Not Working
Seven repeating Excelerator status-light blinks point to the limit-switch circuit. Genie specifically calls out terminal connections and shorted or pinched switch wires.
Genie Excelerator 8 Blinks: Wall Console Is Locked
Eight repeating Excelerator status-light blinks point to vacation/Sure-Lock mode on the wall console—not a failed remote or receiver.
Genie Excelerator 1 Blink: Motor Drive Board Interrupt
One repeating Excelerator status-light blink is a motor-drive-board interrupt, but Genie's own chart also tells you to check door balance, springs, rollers and binding before assuming the board itself has failed.
Genie Excelerator 2 Blinks: Controller Board Interrupt
Two repeating Excelerator status-light blinks are a controller-board interrupt. The homeowner-level check is a controlled power reset; persistent faults move into internal board/interconnect service.
Genie Excelerator 3 Blinks: Opener Overheated or Over-Cycled
Three repeating Excelerator status-light blinks mean the opener is overheated or has been cycled too frequently. Genie's instruction is unusual but clear: leave power connected and let the internal cycle allowance recover.
Genie Green LED 1 Blink: Limits, Safe-T-Beam or Door Obstruction
On Genie 1022/1024/1042/2022/2024/2042/2027 openers, one green powerhead blink is deliberately broad: incomplete limit programming, a closing Safe-T-Beam obstruction, or a door obstruction can all produce it.
Genie Green LED 2 Blinks: UP Limit, Wiring or Safe-T-Beam Branch
Two green powerhead blinks on Genie 1022/1024/1042/2022/2024/2042/2027 openers span several branches: incomplete UP-limit programming, powerhead wiring/connection problems, sensor misalignment, or continuous Safe-T-Beam obstruction.
LiftMaster 2500B, 2500D, 3500 & 3850: 5, 6 or 7 Diagnostic Flashes
Separate RPM-sensor, coasting and motor-circuit branches on the legacy DC diagnostic chart instead of treating every motor-unit flash as a sensor problem.
LiftMaster Legacy DC 10, 11, 12 & 13 Flashes: Force / Travel Direction Guide
Decode the direction-specific force branches for LiftMaster 2500B, 2500D, 3500 and 3850 without using a force adjustment to hide a binding door.
LiftMaster 2500B / 2500D / 3500 / 3850 — 15 Flashes (Bad CRC)
A 15-flash legacy DC code is an electronics/logic-board branch, not a safety-sensor alignment code.
Craftsman Garage Door Opener Diagnostic LED: 1–6 Flashes Explained
How to read the older Learn-button diagnostic LED without mixing it up with newer UP/DOWN-arrow codes or a model-specific chart.
Craftsman UP/DOWN Arrow Diagnostic Codes: How to Read the Pair
A model-aware guide to Craftsman DC opener codes such as 1-UP/2-DOWN and 4-UP/1-DOWN without translating them into the older single-LED flash chart.
Marantec Synergy Error Codes 7–36: Numeric Fault Display Guide
A model-aware guide to the verified numeric fault table shared by Marantec Synergy 200- and 300-series owner manuals.
Marantec M4500e / M4700e / M4900e Fault Codes: Read the 8-LED Display
Translate the verified M4500e/M4700e/M4900e eight-LED fault sequence into codes without treating it like a Synergy or M55 numeric display.
Craftsman 139.53918D Diagnostic LED: 1–5 Flashes Explained
An exact-manual guide to the 139.53918D Learn-button diagnostic LED, including the model-specific 5-flash RPM/travel-module branch that should not be replaced by a generic Craftsman chart.
Marantec M55 Error Codes 7–35: Exact Numeric Display Guide
Decode the exact M55 numeric error display without borrowing the Synergy or EOS eight-LED tables, including M55-only coverage for code 33 and the verified 7–35 fault set.
Linear LDO33 / LDO50 Flash Codes 1–6: Courtesy-Light Diagnostic Guide
Decode the shared six-condition LDO33/LDO50 courtesy-light table without importing LDCO800 or later LDCO850/852 meanings.
Linear LDCO800 Flash Codes 1–7: Exact Lamp-Flash Troubleshooting
Read the LDCO800 seven-condition lamp table correctly, including the model family's seventh-flash encoder/limit branch.
Linear LDCO850 / LDCO852 Trouble Codes: Door Flashes vs Battery Beeps
Separate the 1–7 door-operation flash/beep table from the 2/4/5 battery-alarm beep table before diagnosing these smart DC openers.