had these codes pop up on my computer and not sure what they are...

P1626 << this one i looked up in my Haynes manual and said... Serial data communication failure with vehicle theft deterent controller (no password)

my security light has come on a couple of times when i have been driving but goes away when i turn the truck off....

U1064<<< and this code i have never seen before. thought it was really unusual since it starts with a U

any help from any one would be great. thanks

-John