Check Engine light came on, the XTM-4 light came on, & D is Flashing. Help!

What is your question?

It's like it has No Passing Gear and Overdrive is not kicking in. A mechanic friend, said: It sounds like Speed Sensor and some valve or something behind a plate on side of Tranny? Transmission was replaced 1½ years ago, was running fine! He thinks the Honda Dealership did not put some old parts on it when replacing it?