Error code check sheet
LiftMaster Error Code 4-6
Code 4-6 commonly points to safety sensor obstruction, misalignment, wiring, or a blocked closing path.
Do not loosen, wind, unwind, or adjust torsion springs, extension springs, lift cables, drums, or bottom brackets. Use these checks for opener controls, sensors, remotes, lights, and simple observations.
Diagrams and printables
Sensor alignment diagram
Learn button location
Error-code flowMost likely causes
| Likely cause | First safe check | Stop point |
|---|---|---|
| Blocked sensor beam | Check this before replacing parts or changing force settings. | Stop if the door is heavy, crooked, or the spring/cable system is involved. |
| Misaligned photo eyes | Check this before replacing parts or changing force settings. | Stop if the door is heavy, crooked, or the spring/cable system is involved. |
| Loose sensor wire | Check this before replacing parts or changing force settings. | Stop if the door is heavy, crooked, or the spring/cable system is involved. |
| Sun glare or dirty lens | Check this before replacing parts or changing force settings. | Stop if the door is heavy, crooked, or the spring/cable system is involved. |
Step-by-step checks
Remove objects from the door path
Result: continue only if the door and opener respond normally.
Wipe both sensor lenses
Result: continue only if the door and opener respond normally.
Check whether both sensor LEDs are steady
Result: continue only if the door and opener respond normally.
Gently realign brackets
Result: continue only if the door and opener respond normally.
Inspect low-voltage sensor wires
Result: continue only if the door and opener respond normally.
On the bench
Fresh remote battery, flashlight, soft cloth, step ladder, phone camera for blink patterns.
Stop and call
The door is heavy by hand, crooked, off track, has broken spring parts, or the opener strains without moving the door.
Reset note
Unplug the opener for 30 seconds only after noting lights or codes. Do not erase remote memory unless pairing is the actual problem.
Common questions
Should I bypass the safety sensors?
No. Sensors are a required safety system. Fix alignment, wiring, or obstruction instead.
Can I increase force to make the opener close?
Only after the door moves freely by hand and the sensor path is clear. Force changes should not hide a binding door.
Why does the wall button work but the remote does not?
That usually points to lock mode, remote battery, signal range, or lost programming rather than a failed motor.