4-1 Moderate Easy DIY

LiftMaster Garage Door Opener 4-1 — Door obstruction detected

LiftMaster Garage Door Opener · Error code 4-1

What 4-1 Means

Opener sensed contact with an obstruction while closing and reversed, or hit resistance while opening and stopped. Repeat detections in one cycle latch the 4-1 alert.

Symptoms

  • Door reverses immediately or partway down
  • Door stops on the way up
  • Up arrow blinks 4, down arrow blinks 1
  • Recently happened after cold snap or new weather seal

Common Causes

1
Object in the door's path

Trash can, ladder, parked car bumper triggering contact reversal.

2
Bottom seal frozen to floor

Ice bonding seal to concrete creates instant resistance.

3
Damaged or bent track

Track ding or roller hangup causing a hard spot in travel.

4
Spring weakening

Door is heavier than the down-force was calibrated for.

5
Brand-new heavy weather seal

Stiff replacement seal increases close force needed.

How to Fix It

  1. Inspect the floor and track for anything in the door's path.
  2. In freezing weather, break the seal free with a putty knife and salt the threshold.
  3. Sight down the track for kinks, bends, or loose lag bolts.
  4. Pull the emergency release and confirm the door balances at the halfway mark.
  5. Lube rollers, hinges, and track joints with white lithium grease.
  6. If still tripping, slightly increase down-force (1/8 turn) — then re-test reversal with a 1.5-inch block.
  7. Replace weak spring or worn rollers if balance test fails.

Parts You May Need

If diagnosis points to a failed part, these are the common replacements. As an Amazon Associate we earn from qualifying purchases.

Common replacement Bottom weather seal (size to door) View on Amazon→ Common replacement White lithium grease View on Amazon→

More LiftMaster Garage Door Opener Codes

1-1 1-1 — Safety sensor wire short or reversed 1-2 1-2 — Safety sensor wire shorted or reversed 1-3 1-3 — Door control or wire issue 1-4 1-4 — Safety sensors misaligned 1-5 1-5 — Motor overheated or stuck 1-6 1-6 — Logic board or motor relay failure

All LiftMaster codes → All garage door opener codes →

Verified against manufacturer documentation: liftmaster.com

Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician.