If you have tried the instructions in the manual with out success, you will have to use the secondary method in the manual.

1) Make sure the antannae on the opener motor is hanging down.

2) Make sure the car is directly under the or as close as possible to the antannae.

3) Clear all codes previously set.

4) You will have to use the "Learning/Reset" switch on the opener. It is usually at the back of the unit and can either be red, white or green. Then follow instruction in the manual.

Hope this helps.