Display shows “16”; courtesy light flashes rapidly; door will not move.

Safety first: Never operate the opener with safety sensors bypassed. This is a serious hazard.

• Inspect sensor wiring: At the opener head, remove any jumpers or non‑standard wiring between the safety sensor terminals. Each sensor should have its own pair of wires.
• Verify genuine sensors: Ensure you are using Marantec‑compatible photo eyes. Incompatible sensors or resistors used to fake a sensor can trigger this fault.
• Reconnect correctly: Wire the sensors per the Marantec wiring diagram, maintaining polarity and using proper low‑voltage cable.
• Test sensors: Align and test the sensors until both LEDs indicate a solid beam. Then command the door to close; the error should clear.
• If board still reports tamper: The control board’s safety circuit may be damaged and require replacement.