I have a 2014 Volkswagen Polo. I have two keys, and both work perfectly. They can unlock and lock the car with the remote, and start the car as well. Recently, my car battery died, so I had to disconnect it for about a week, which caused the car to lose power.
When I reconnected the new battery, neither of my remotes could operate the central locking. They wouldn't lock or unlock the car. When I pressed any button, there was no response, except for the red light occasionally flashing.
I tried the resynchronization method from the car manual, but it didn't work. I also replaced the batteries in both remotes, but that didn't help either. I tried different methods and watched YouTube videos to resynchronize the remotes, but nothing worked. The keys can still manually unlock the car, and both remotes can start the car, but they just can't lock or unlock it. I was told I might need to reprogram them with ODIS or VCDS. After doing a lot of research and seeing recommendations on YouTube, I decided to order VXDIAG, and it turned out to be a great device that solved my problem. Besides that, I also have a GM and a Ford, so I purchased the SE PRO, thinking it would solve everything once and for all.