Guardian opener attempts to run but stops quickly, LED shows code “4” or four flashes, motor hums or jerks.

Safety first: Unplug the opener. Do not continue to run a stalled motor; it can overheat and cause damage or fire risk. Springs are dangerous—do not adjust them yourself.

• Disconnect door: Pull the emergency release to separate the door from the trolley. Try running the opener with no door load. If it runs normally, the problem is with the door, not the opener.
• Check door balance: Lift the door by hand. If it is extremely heavy or cannot be lifted, a torsion or extension spring may be broken. Call a professional door technician.
• Inspect rail and trolley: Look for bent rail sections, a jammed trolley, or foreign objects in the rail. Clear any obstructions and ensure the trolley moves freely.
• Inspect drive system: For chain/belt drive Guardian models, check the drive sprocket on top of the opener and the belt/chain for missing teeth, kinks, or binding. Realign or replace damaged parts.
• Allow motor to cool: If the opener has been run repeatedly, let it cool for 20–30 minutes, then test again with the door disconnected.
• Replace motor or head if needed: If the motor still hums and trips overload with no load on the rail, the motor or internal gearbox is likely failing and the opener head should be replaced.