Chromatic 1

Hey guys my father in law has a 2008 Chevrolet express can 1500 with a 4.3 l engine in it.. the other day a code came up on the dash reduced engine power I hooked my scan tool up to it and got two codes a p0123 which is a throttle position sensor a circuit high input and p0223 throttle position sensor switch b circuit high input code I was just curious about them so I looked online and found a tsb #11-06-04-007b could any one tell me if this is legit I called the dealership where I am from and they said that their computers were down and they had to diagnose it for themselves which would cost about 150 an hour as I do not have this cash at the time was just curious thanks guys