Garage Door Opener Error Codes: Chamberlain, LiftMaster & Genie

Common Symptoms

• Opener LED blinks a specific number of times repeatedly
• Display shows a numbered error code (4, 5, 6, etc.)
• Opener activates then immediately reverses without operating the door
• Opener doesn't respond to wall button or remote
• Opener emits a series of beeps before stopping

Most Likely Causes

1. 1

   Sensor Fault — 4 Blinks (Chamberlain/LiftMaster)

   Four blinks on a Chamberlain or LiftMaster opener indicates a safety sensor problem. Either the sensors are misaligned, there's an obstruction in the beam path, or the sensor wiring has a fault. The sending sensor (yellow/amber light) should have a solid light; the receiving sensor (green light) should also be solid. A blinking or off light indicates the fault.

2. 2

   Sensor Wire Short — 5 Blinks (Chamberlain/LiftMaster)

   Five blinks indicates a short circuit in the safety sensor wiring — the white and white/black wires have touched somewhere along the run from the opener to the sensors. Inspect the entire wire run for staples that have pinched through the insulation or wire that has been pinched in the door track.

3. 3

   Logic Board or Motor Fault — 6 Blinks (Chamberlain/LiftMaster)

   Six blinks indicates a problem with the motor or logic board. Disconnect power for 30 seconds and reconnect. If the code persists after a power reset, the logic board or motor may need replacement.

4. 4

   Genie Blink Codes

   Genie openers use a different blink sequence. 1 blink: safety sensors obstructed or misaligned. 2 blinks: safety sensor wiring issue. 3 blinks: upper limit switch out of adjustment. 4 blinks: safety sensor short circuit. Genie openers with a numeric display show codes like Error 1 (sensor), Error 3 (limit), Error 4 (travel module).

5. 5

   Limit Switch Out of Adjustment

   If the opener thinks the door is in a different position than it actually is, it will refuse to operate or will reverse prematurely. This generates a limit fault code. Most modern openers use electronic limit setting — a manual re-learning sequence resets the up and down travel limits.

Quick DIY Checks

1. 1Count the LED blinks: the opener will blink, pause, then repeat the same count. Write down the blink count — this is your error code. On openers with a display, note the numeric or alpha code shown.
2. 2For 4 blinks (Chamberlain/LiftMaster) or 1 blink (Genie): go to both sensors at the bottom of the door tracks. Clean the lens of each sensor with a dry cloth. Check that both lights are steady (not blinking). Loosen the mounting wing nuts on the receiving sensor (typically green light) and adjust until both lights are solid, then retighten.
3. 3For 5 blinks (Chamberlain/LiftMaster) or 2 blinks (Genie): inspect the white sensor wires from the opener head unit all the way to each sensor. Look for any point where the wire is stapled, pinched in the track, or has the insulation damaged. Repair or replace damaged wiring.

Repair vs Replace

Recommended Tools & Parts

• Chamberlain/LiftMaster Safety Sensor Kit

  OEM safety sensor pair for Chamberlain and LiftMaster openers. Solves most 4-blink and 5-blink sensor fault codes.

  $25–$50

  Buy on Amazon →

• Garage Door Opener Logic Board

  Replacement logic board for Chamberlain/LiftMaster openers. Model-specific — search by your opener's model number on the label inside the light cover.

  $60–$120

  Buy on Amazon →

• Genie Garage Door Opener Sensor Kit

  Replacement photo-eye sensor kit for Genie openers. Resolves Error 1 and Error 4 sensor fault codes.

  $20–$40

  Buy on Amazon →

Links are Amazon affiliate links (tag: fixitfastai-20). Prices are estimates.

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