Error 12

1. The error code is letting us know there is a sensor issue


Remove the receiving sensor(green LED) from bracket. You can do so by taking off the wing nut.
Point the sensor away from the sending sensor, so that the LED light is completely off.
Once the LED light is off, wait 10 seconds.
Slowly rotate sensor back until it lights again. When you have a strong green light, put it back into the bracket and put the wing nut back on.

If door still doesn't close then we will need to isolate it further by the following:

Remove the sensors from the brackets.
Remove the wires from the wire nuts or cut the sensor wires 12" from the sensors.
Strip both ends of wires from each sensor and twist like colored wires together. Proceed with both sensors to the garage door opener motor unit.
Remove existing wires from the white and grey terminals on the back of the operator.
Attach or insert white wires into the white terminal and black/white striped wires into the grey terminal.
Point the sensors at each other - if both sensor LED's turn on, there is an issue with your wiring. Replace the wires between the opener and the sensors. If the LED's DO NOT turn on, replace the sensors.

Thanks