You have not shown any C# code that is receiving serial data, though the Arduino seems to be sending some.QuoteThe ultimate goal would be to send a message in the format of x:n where x is a letter representing Throttle or Steering(T or S), the colon separates it, and the n is a value between 0 and 255.Even better would be to send <x:n> where < is an SOP and > is an EOP (start and end of packet)