How to replace app sensor/pedal assembly

I don't think they failed either, but I keep getting error p1516, and the TAC module has been replaced (no fix). The mech is telling me they are normally replaced at the same time (TB and APP). I am going to do it myself, so I guess I could try one at a time. The throttle body is cheaper so I guess I could start with that, but I hate to replace it if it isn't the problem. He had it hooked to the scan tool and said there really wasn't any sign of an issue when the error occurred. He is just saying replace both and hope really.

That is the only code, and there is no low voltage issues. I found the same TSB, but it doesn't go on to say what the diagnostic test for intermittent concerns consist of. I'm sure the mech has that info, and I assume followed those procedures (I hope). It is annoying because it only occurs in the morning. I'll start it fine, drive about 3 miles and it sets. If I restart 6 or 7 times it will allow me to drive again. Then after it sits for a little while, the check engine light goes off and it is good for the rest of the day.

The G104 ground has been bypassed, the mech grounded the TAC to the battery. I can't get him to pay any attention to the G013 ground. I was able to get my hand on it, and it is connected. I couldn't get my arm in there enough to get a ratchet on it, and I don't know how to bypass it. Again, every time I mention it, he says if it were a ground wire then the bypass of G104 that he put it would mitigate it.