After working for quite a long time my auto tune quit changing channels. I can set the auto tune and it shows it is set but it does not change the channel. I wonder if I accidentally hit a button on the remote and changed something.
You might just need to wait several hours for the Guide Data to rebuild. If that doesn't help, post back with details about how exactly you're setting up the Autotune. It should work on the D12 SD Receiver.