91accord "s" light blinkin, shifting problems, i ned to use D2 to start runthen use d3 and d4 and the speedometer not work. I tried another tcu and did the same thing.

 

go to our DIY section and there is a post on how to retrieve ECU codes using the service short connector. Find out what code is stored per those instructions then post it here. If you are having a hard time reading it you can always do a video of the blink pattern with your cell phone or whatever you have and post that so we can help.