I just installed New Air Cleaner and Exhaust and also an arlen ness cheap shot tuner( which i think is what tripped it...)

I started the bike up and everything works fine except for the speedometer and the red key light is on. Also when i was installing the turner i disconnected the battery all the way to get a dropped socket.
Bike runs good. I ran the diag mode and i got the

SP code

U1255 Missing Message at Speedometer EFI
U1255 Serial Data Error/Missing Message EFI
U1255 Serial Data Error/Missing Message Instruments
U1255 Serial Data Error/Missing Message TSM/TSSM

Is this something i have to take to the dealer to get reset and fixed or is this a DIY easy job.

 

I don't know how that tuner works, but before bringing it to a dealer I would check the connection and pins. Then pull the tuner and see how it runs and if it still throws codes.
If you can clear the codes and they don't come back, it could be a defective unit or wrong settings.

 

I ran a Ness Cheap Shot on my '04 Softail and never threw a code. In fact it is still on the bike but disconnected in case the PCIII ever pukes. You may want to check your connections.