Opener will not close door; lights flash four times; door may move slightly then stop.

Safety first: Unplug the opener before removing covers. Use caution around sharp metal edges inside the opener chassis.

• Reset travel limits: On newer Craftsman openers with electronic limits, press and hold the PROGRAM or SETUP button per the manual to enter travel setup mode. Run a full open and close cycle to re-learn limits.
• Check mechanical limit nuts (older units): On older chain-drive Craftsman models, remove the light cover and inspect the limit adjustment nuts on the threaded shaft. Ensure they are not stripped and are positioned so the door fully opens and closes without hitting the stops too early.
• Inspect travel module: On belt and chain drive units with a travel module attached to the motor shaft, check the wiring connector for a secure fit. Look for cracked plastic or signs of water intrusion.
• Power cycle: After adjustments, unplug the opener for 30 seconds, then plug back in to reset the logic board. Test door operation from the wall button.
• Replace faulty module: If the 4-flash error persists and limits cannot be set, replace the travel module or limit switch assembly specific to your Craftsman model.