Opener runs briefly then stops; logic board LED flashes 4 times, pause, then 2 times (4-2).

Safety first: A door that is too heavy or unbalanced can cause serious injury. If the door is difficult to lift manually, call a professional door technician.

Steps to fix:

• Check door balance and hardware: Disconnect the opener and move the door by hand. Correct any binding, damaged rollers, or track issues before proceeding.
• Inspect motor harness: With power off, open the housing and inspect the motor wires and connector for melted insulation, discoloration, or loose pins.
• Allow motor to cool: If the opener has been run repeatedly, allow 30 minutes for the motor’s thermal protector to reset, then test again.
• Measure motor resistance: Using a multimeter, check the motor windings for continuity and shorts to ground. Replace the motor assembly if readings are out of spec.
• Replace logic board if necessary: If the motor tests good but the 4-2 code persists, the current-sensing circuit on the logic board may be faulty.