Garage door stops or reverses randomly; opener lights flash 2 times, pause, then 3 times (logic board LED code 2-3).

Safety first: Unplug the opener before opening the motor housing. Capacitors inside can hold charge; avoid touching exposed circuitry.

Steps to fix:

• Inspect travel module: On many Chamberlain models, a travel module (limit encoder) is mounted near the motor or rail. Check that its connector is fully seated on the logic board and that the wiring is not pinched.
• Check RPM sensor: Some models use an RPM sensor disc and optical sensor on the motor shaft. Verify the disc is not cracked or rubbing and that the sensor is clean and aligned.
• Reseat connectors: Gently unplug and replug the travel module and motor harness connectors to clear oxidation.
• Power cycle and test: Restore power and run a full open/close cycle. If the 2-3 code returns, the travel module is often the failed component and should be replaced with a Chamberlain-compatible part.
• Replace logic board if needed: If a new travel module and good wiring do not resolve the issue, the logic board’s sensor input may be defective and require replacement.