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Garage Door Opener | Diagnostic Codes and UP/DOWN Flashing Lights

TROUBLESHOOTING  ·  SECURITY+ 2.0 & 3.0  ·  UP/DOWN ARROW CODES

If your garage door opener UP and DOWN arrows are flashing, it has detected an issue that may stop the door from operating normally. Use what you're seeing the door do, or the flash count, to find the fix below.

Identify Your Opener

Security+ 2.0

  • Yellow Round LEARN button
  • UP and DOWN adjustment arrows

Security+ 3.0

  • White Round LEARN button
  • UP and DOWN adjustment arrows

Both use the same diagnostic codes and steps. No arrows on your opener? See the companion diagnostic guide for openers without arrows instead. Diagnostic Codes for Chamberlain & Liftmaster Garage Door Openers

Quick Answer

Select the row below that matches what your door is doing, or the code you counted, to expand the fix.

How to Identify the Diagnostic Code

 
The UP and DOWN arrow lights flash in a repeating pattern. The number of UP flashes and DOWN flashes identifies the diagnostic code. 

  1. Locate the UP and DOWN arrows on the opener.

  2. Count the number of UP arrow flashes.
  3. Count the number of DOWN arrow flashes.
  4. Wait for the pattern to repeat to confirm what you counted.

Examples: 1 UP + 1 DOWN = Code 1-1. 1 UP + 5 DOWN = Code 1-5. 4 UP + 2 DOWN = Code 4-2.

UP and DOWN diagnostic arrows on the garage door opener

Start Here: What Is Your Door Doing?

Select a row that matches what your opener is doing or matches the flashing UP and Down arrows on your opener. Click on the row to expand the full fix. 

 

Door starts closing, then reverses
1 UP, 1 DOWN 1-1 +

Code 1-1 | Safety Sensors Blocked, Misaligned, Disconnected, or Wire Break

Quick Answer

One of your safety sensors is likely blocked, misaligned, or unplugged. Clear the sensor beam and check that both lights glow steady.

What are safety sensors?+

Two small plastic boxes, mounted a few inches above the floor on each side of your garage door track, facing each other. One sends an invisible beam and the other receives it. If something blocks that beam, the door won't close.

What you'll notice

This code appears when a sensor is blocked, misaligned, disconnected, or unable to communicate with the opener for more than four seconds.
  • The door starts closing, then reverses.
  • The door stays open and will not close.
  • Depending on the opener model, the main work lights may flash 10 times.
  • If no light bulbs are installed, the opener may make a clicking sound.
Not every opener model or software version shows the same light or sound pattern.

💡 Quick check: Clear the door's path of people, pets, and objects. Press and hold the wall control button until the door is fully closed. If the door closes only while you hold the button, the safety sensor system requires troubleshooting.

How to fix it

  1. Remove anything blocking the invisible beam between the two sensors.
    Boxes, toys, plants, tools, and other objects can interrupt the beam.
    ✅ Success: The path between the sensors is clear.
  2. Check the two sensor lights.
    • One sensor has an amber light and sends the beam.
    • The other sensor has a green light and receives the beam.
      • Green light off or blinking: The sensors are likely out of alignment. Loosen the wing nut on the receiving sensor, gently aim the sensors toward each other, and tighten the wing nut once the green light remains steady.
        ✅ Success: The green sensor light stays on without flickering.
      • Both lights off: The sensors may not be receiving power or may have become disconnected. Check the sensor wires at the opener and make sure they are connected securely.
        ✅ Success: The sensor lights turn on after restoring the connection.
      • Both lights glowing steadily: The sensors are aligned, receiving power, and communicating correctly.
  3. If the sensor lights still do not work correctly after checking the alignment and connections, perform a short-wire test.
What is a short-wire test?+

A short-wire test temporarily connects the safety sensors near the opener. This helps determine whether the problem is with the sensors or with the wire running through the garage walls.

⚠️ Technician Recommended 

  1. Disconnect power to the garage door opener.
  2. Remove the safety sensors from their brackets.
  3. Cut each sensor wire approximately 6 inches from the safety sensor.
  4. Strip approximately 7/16 inch (11 mm) of insulation from each wire.
  5. Connect the sensors directly to the wire terminals on the opener (usually located on the back or side of the motor unit).
  6. Restore power and check the sensor lights.

✅ Sensors work when connected near the opener: The wire running from the sensor location to the opener may be damaged.

✅ Sensors do not work when connected near the opener: One or both safety sensors may need to be replaced. 

If the issue continues

If the diagnostic code remains after checking the sensor path, alignment, connections, and installed wiring, the safety sensors may need to be replaced.

Contact a local garage door professional for assistance. Find a LiftMaster Dealer.

Related articles

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Door stays open and won't close at all, no reversal
1 UP, 2 DOWN 1-2 +

Code 1-2 | Safety Sensor Wires Reversed or Shorted

Quick Answer

The safety sensor wiring is likely reversed or shorted. Check that wire colors match at both ends, and look for pinched or damaged wire.

What you'll notice

  • The door will not close.
  • When using a wall control or keypad, the door may move an inch or two and return to its starting position.
  • The opener lights may flash 10 times.
  • If no light bulbs are installed, the opener may make a clicking sound.

How to fix it

  1. If the garage was prewired when the opener was installed, confirm that the same wire colors connect to the same spots at the sensors and opener.
  2. If the garage was not prewired, check the openrer to confirm:
    • White wires connect to the white terminal.
    • Black-striped wires connect to the black terminal.
  3. Inspect along the wire for staples, nails, cuts, or other visible damage.
  4. Correct crossed wires and remove anything pinching the wire.
✅Success looks like: The sensor lights work normally, and the door closes.

If the issue continues

Perform a short-wire test to determine whether the problem is with the installed wiring or the safety sensors.
  • Sensors work during the short-wire test: The installed wire may need to be repaired or replaced.
  • Sensors do not work during the short-wire test: One or both safety sensors may need to be replaced.
What is a short-wire test?+

A short-wire test temporarily connects the safety sensors near the opener. This helps determine whether the problem is with the sensors or with the wire running through the garage walls.

⚠️ Technician Recommended 

  1. Disconnect power to the garage door opener.
  2. Remove the safety sensors from their brackets.
  3. Cut each sensor wire approximately 6 inches from the safety sensor.
  4. Strip approximately 7/16 inch or 11 mm of insulation from each wire.
  5. Connect the sensors directly to the wire terminals on the opener (usually located on the back or side of the motor unit).
  6. Restore power and check the sensor lights.

✅ Sensors work when connected near the opener: The wire running from the sensor location to the opener may be damaged.

✅ Sensors do not work when connected near the opener: One or both safety sensors may need to be replaced. 

Related articles

Garage Door Safety Sensors | How to Wire to Opener

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Door reverses, stops, or struggles at any point while closing, not just near the floor
4 UP, 1 DOWN 4-1 +

Code 4-1 | Resistance While Closing

Quick Answer

The opener detected an unforseen change in RPM's while attempting to close the garage door. 
This may happen if something blocks the door or if the door becomes difficult to move.
Remove visible obstructions and inspect the door rollers and hinges before testing the door again.

What you'll notice

The door reverses, stops, or struggles at some point while closing. The problem can occur anywhere in the closing cycle.
The opener stops or reverses the door when it detects more resistance than expected.

How to fix it

  1. Inspect the garage door path and tracks.
  2. Remove trash cans, tools, broom handles, or other objects in or near the door path.
  3. Check the rollers and hinges for visible obstructions or wear.
  4. Lubricate the rollers and hinges according to the manufacturer's maintenance instructions.
  5. If the door attempts to travel farther after reaching the floor, reprogram the travel limits.

⚠️ Caution: 

Do not disconnect an open garage door from the opener. A weak spring, broken spring, or unbalanced door could cause the door to fall unexpectedly.
Never adjust or loosen springs, cables, pulleys, or brackets. Contact a trained door technician if you cannot identify the obstruction.
✅Success looks like: The door closes fully without stopping, struggling, or reversing.

If the issue continues

If the door continues to reverse, stop, or struggle after removing visible obstructions, contact a local garage door professional for assistance. Find a LiftMaster Dealer.

Related articles

Garage Door Won't Fully Open or Close

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Door stops and reverses right before touching the floor
4 UP, 3 DOWN 4-3 +

Code 4-3 | RPM Lost While Closing

Quick Answer

The opener's motor speed dropped unexpectedly while attempting to close the garage door. Start by checking for anything that could interfere with normal door movement.

What you'll notice

The garage door starts closing but stops and reverses before reaching the floor.
The opener detected a drop in motor speed while the door was closing.
  
What is RPM?+

RPM measures how fast the opener's motor is spinning. You won't see this number anywhere on the opener, it's just how the opener measures motor speed internally to sense whether something is blocking the door.

How to fix it

Check the travel module. The travel module is an internal opener component that tracks the door's movement and position. The opener uses this information to monitor the door as it opens and closes.
  1. Inspect the garage door path and tracks.
  2. Remove trash cans, tools, broom handles, or other visible obstructions.
  3. Check the rollers and hinges for visible obstructions or wear.
  4. Test the door again.

✅Success looks like: The door closes fully without stopping or reversing near the floor.

If the issue continues

The travel module, RPM sensing system, or another internal opener component may require inspection.
Contact a local garage door professional for assistance. Find a LiftMaster Dealer.

Related articles

(Garage Door Won't Fully Open or Close


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Door stops before it's fully open
4 UP, 2 DOWN 4-2 +

Code 4-2 | Resistance While Opening

Quick Answer

The opener detected an unforseen change in RPM's while attempting to close the garage door. Something is making the door harder to open than the opener expects. Check for obstructions, then test the door's balance.

What you'll notice

The garage door stops before reaching the fully open position.
The opener stops the door when it detects more resistance than expected during the opening cycle.

How to fix it

Check for an Opening Obstruction

  1. Close the garage door using the wall control.
  2. Inspect the garage door path and tracks.
  3. Remove trash cans, tools, broom handles, or other visible obstructions.
  4. Test the door again. 
  5. If it still does not fully open, check the balance of the garage door.
✅Success looks like: The door opens fully without stopping early.

⚠️ Caution: Never adjust or loosen the door's springs, cables, pulleys, or brackets yourself, they're under extreme tension. If the balance test shows the door is out of balance, contact a local garage door professional for assistance. Find a LiftMaster Dealer.

If the issue continues

If the door continues to stop before reaching the fully open position, contact a local garage door professional for assistance. Find a LiftMaster Dealer.

Related articles

Garage Door Won't Fully Open or Close

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Door stops before it's fully open (motor speed drop)
4 UP, 4 DOWN 4-4 +

Code 4-4 | RPM Lost While Opening

Quick Answer

The opener detected an unexpected drop in motor speed while opening. Start by checking for anything that could interfere with normal door movement.

What is RPM?+

RPM measures how fast the opener's motor is spinning. You won't see this number anywhere on the opener, it's just how the opener measures motor speed internally to sense whether something is blocking the door.

What you'll notice

The door stops before reaching fully open.

How to fix it

  1. Inspect the garage door path and tracks.
  2. Remove trash cans, tools, broom handles, or other visible obstructions.
  3. Check the rollers and hinges for visible obstructions or wear.
  4. Test the door again.

If the code returns, perform a door balance test.

During the balance test, manually disconnect the garage door from the opener using the emergency release rope and attempt to open the door by hand.
    • If the door is difficult to open or will not open, inspect the torsion springs above the garage door for visible damage or a broken spring.
    • If a spring appears broken, stop troubleshooting and contact a local garage door professional for assistance.
    • If the door opens and closes normally during the balance test, reconnect the door and continue troubleshooting.
✅Success looks like: The door opens fully without stopping early.

If the issue continues

If the door passes the balance test and the diagnostic code still appears, the travel module, RPM sensing system, or another internal opener component may require inspection.
Contact a local garage door professional for assistance. Find a LiftMaster Dealer.

 

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Opener hums or clicks, and the door barely moves or doesn't move
1 UP, 5 DOWN 1-5 +

Code 1-5 | RPM Not Detected

Quick Answer

The opener didn't sense the motor spinning right after a command, that doesn't automatically mean the motor itself has failed. What happens next, humming, clicking, or a few inches of movement, points to the right fix below. 

What is RPM?+

RPM measures how fast the opener's motor is spinning. You won't see this number anywhere on the opener, it's just how the opener measures motor speed internally to sense whether something is blocking the door.

What you'll notice

  • The opener hums or clicks.
  • The door moves less than 6 to 8 inches, then stops and/or reverses.
  • The door doesn't move at all.

How to fix it

Follow the path that matches what you're seeing:

 

✅Success looks like: The door completes a full open or close cycle, and the diagnostic code clears.

If the issue continues 

The motor, travel module, or another internal opener component may require inspection.
Contact a local garage door professional for assistance. Find a LiftMaster Dealer.

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Door opens all the way, then drifts back down or moves on its own
1 UP, 6 DOWN 1-6 +

Code 1-6 | Unexpected Door Movement

Quick Answer

The opener detected door movement without receiving a command. This is most often caused by an unbalanced door or by manually moving a door connected to a jackshaft opener.
Check the door's balance and reconnect the emergency release if it was pulled.

What you'll notice

The opener detected movement that it did not start.
If the garage door is no longer properly supported by the spring system, the door's weight can cause it to move downward on its own. The opener may interpret this movement as a falling door and attempt to return the door to the fully open position.
On a residential jackshaft opener, this code may also appear when the door is moved by hand while the emergency release is disconnected. The opener can still detect the garage door shaft turning during manual movement.
  • The door drifts down after reaching the fully open position.
  • The opener attempts to pull the door back open.
  • The code appears after manually moving a door connected to a jackshaft opener.

💡 Note: A jackshaft opener is mounted on the wall next to the garage door instead of on the ceiling.

How to fix it

  • Door drifts down after opening: The door may be out of balance. See  How to test the balance of a garage door 
  • Code appears after manually moving a door connected to a jackshaft opener: The 
    emergency release rope may still be disconnected. Reconnect the garage door to the opener and operate the opener again.  See How to Manually Open or Close a Garage Door for complete instructions and safety information.

⚠️ Caution: Never adjust or loosen the door's springs, cables, pulleys, or brackets yourself, they're under extreme tension. If the balance test shows the door is out of balance, contact a local garage door professional for assistance.

✅Success looks like: The door stays fully open, operates normally, and the diagnostic code clears.

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Door won't move, and the opener doesn't seem to recognize its own hardware
4 UP, 5 DOWN 4-5 +

Code 4-5 | Unrecognized Travel Module

Quick Answer

The opener doesn't recognize the travel module that's installed, usually right after a part was replaced. Confirm the correct travel module for your model.

What you'll notice

The door starts closing and returns to the open position, or it does not move and remains open.
The opener uses the travel module to track the door's movement and position. If the module is not recognized, the opener may not allow normal operation or travel-limit programming.

How to fix it

If the travel module was recently replaced:

  1. Find the opener model number on the label attached to the garage door opener.
  2. Check the owner's manual for the correct travel module for your opener model.
  3. If the travel module installed is not the correct part, replace with the correct part found in your owner's manual.
✅Success looks like: The opener recognizes the travel module, the door opens and closes fully, and the diagnostic code clears.

If the issue continues

Contact a local garage door professional for assistance. Find a LiftMaster Dealer.

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Opener doesn't respond to anything at all
2 UP, 1–5 DOWN 2-1 | 2-2 | 2-3 | 2-4 | 2-5 +

Codes 2-1, 2-2, 2-3, 2-4, 2-5 | Logic Board Component Failure

Quick Answer

The opener detected a possible problem with an internal electronic component on the logic board.
Cycle power to the opener. Unplug the opener for 5 seconds, then plug it back in and test the door again. 
What is the logic board?+

The opener's main circuit board, located inside the motor unit's housing, usually behind the light cover or a side panel. 

It receives commands and controls the opener's functions.

What you'll notice

The opener does not respond normally to commands, and another diagnostic condition does not explain the issue.

How to fix it

Power cycle the opener

  1. Disconnect the battery backup if the opener has one.
  2. Unplug the garage door opener from the electrical outlet.
  3. Plug the opener back into the outlet.
  4. Reconnect the battery backup.
✅Success looks like: The opener responds normally to a wall control or remote command, and the diagnostic code clears.

If the issue continues

The logic board may require replacement. Refer to the owner's manual for replacement part information.
Contact a local garage door professional for assistance. Find a LiftMaster Dealer.

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Door ignores a scheduled or app-based command, but the wall button/remote still work
5 UP, 5 DOWN 5-5 +

Code 5-5 | Remote Light Required for Unattended Operation

💡 Note: This code applies to the following LiftMaster and Chamberlain wall-mounted jackshaft openers: 8500W / RJO70, 98022 / RJO101, 98032

Quick Answer

The opener needs a myQ-compatible light installed and paired before it will move the door unattended. Confirm one is installed, or turn off schedules instead.

What you'll notice

As a safety precaution, the opener will not move the door in response to an unattended command without a paired remote light.
This code may appear during initial installation if the included remote light is not detected by opener. 
Remote lights are paired to the opener during manufacturing
This code may also appear if the opener's memory has been cleared.
  • myQ cannot operate the door.
  • A scheduled close does not run.
  • A smart-home automation does not run.
  • Timer-to-Close (TTC) will not close the door at the designated time interval
  • The wall control and remote controls continue to work.

How to fix it

  • Install and plug in the myQ-compatible light: Confirm that a compatible remote light is installed and plugged in to a powered outlet.
  • Reprogram a previously connected light: If the opener memory was cleared, program the remote light to the opener again.
  • If the remote light will not be used: In the myQ app, turn off schedules and automations.
✅Success looks like: 
App-based commands, scheduled closing, and Timer-to-Close (TTC) operate the door after a compatible remote light is detected.

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Door reverses back to open on its own in the middle of closing
3 UP, 5 DOWN 3-5 +

Code 3-5 | Cable Tension Monitor

💡 Note: This code applies to the following LiftMaster and Chamberlain wall-mounted jackshaft openers: 8500W / RJO70, 98022 / RJO101, 98032

Quick Answer

The cable tension monitor detected a condition that could affect safe operation of the garage door. The monitor may be disconnected, incorrectly positioned, damaged, or detecting a loose garage door cable.

What you'll notice

The cable tension monitor is a safety component that monitors for garage door cable slack during closing operations. If the monitor detects cable slack, the opener will stop and reversethe door to the open position.
  • The door starts closing and returns to the open position.
  • The door does not move.
  • On a supported Wi-Fi jackshaft opener with a paired remote light, the light may flash five times after the door returns to the open position.

How to fix it

⚠️ Caution: A loose garage door cable can prevent the door from operating safely. Do not loosen, adjust, or remove garage door cables, springs, pulleys, or brackets. These components are under high tension and can cause serious injury.

If the cable appears loose, frayed, damaged, or off the drum, stop using the garage door and contact a local garage door professional for assistance. Find a LiftMaster Dealer.
  1. Check whether the cable tension monitor has become disconnected.
  2. Reconnect it to the terminals on your openers logic board.
    • Refer to the installation manual for the correct cable tension monitor connection and terminal locations.
  3. Check whether the cable tension monitor is detecting a loose garage door cable.
    If the cable is loose, stop troubleshooting and do not operate the garage door.
  4. Check the cable tension monitor roller.
    If the roller is  not resting on the top of the garage door cable, refer to the installation manual for the correct roller position.
  5. Inspect the cable tension monitor wire for visible damage.
    If the wire appears cut or damaged, repair the wiring. 
⚠️ The cable tension monitor is a safety component. If the monitor, its wiring, or the garage door cable appears damaged, contact a local garage door professional for assistance. Find a LiftMaster Dealer.
✅Success looks like: The cable tension monitor is connected and positioned correctly, the door closes fully, and the diagnostic code clears.

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💡 Note: Don't see your code on this list? Check your opener's owner's manual for the full list of diagnostic codes for your model.

 

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Garage Door Opener | Diagnostic Codes and UP/DOWN Flashing Lights