car wont start. on 2007 Scion tC

i replaced the speed sensor on the top of the transmission and after replacing it. i try starting the car and it wont stay on for longer that 2 sec and its not shooting any codes.

Asked by for the 2007 Scion tC
EVERYTHING got plugged back in? Won't hurt to double check...
1 more answer
How did you check for codes?