2003 Prius: P1128 and P3191 Unable to remain Started.

Hello, I am new here and own a 2003 Prius. I hope I am posting this story in the correct forum, if not I apologize, and please guide me as to where it should be please. I had over 7 years of carefree driving
from it, but one day in April 2019, I started the prius up and it started to shake. It then
was no longer able to remain started from that point. I am able to start it up but with a set
of two "codes" P1128 and P3191. This began a long grueling search by many mechanics
to try and find the answer to why it "powers down" by the computer after about 10 seconds.
We then removed the entire "Throttle Body" and cleaned it., Mechanic checked the motor
of the throttle body by attaching an "external electric" source to the motor to see if the throttle
moves, which it did. We also purchased a brand new "throttle position sensor". The mechanic
removed the "Entire Hybrid Battery and tested each individual cell" all were well within operating range.
He opened the glove compartment and tested to see if the computer or something in the glove compartment was communicating with the throttle body components. He also check the spark plugs. We replaced the 12 volt trunk battery with a brand new one. We just can't get this 2003 prius to start back to life again.
I am also getting a Error on the Dash board light with a "red TRIANGLE" and a Car with an Exclamation
point in the middle of it, on the Dashboard" screen. Can someone help me solve this riddle. I heard that there may be a "RELEARN PROCESS". We also completely recharged the hybrid battery and put it back into the vehicle. Is there a "RELEARN PROCEDURE" that we must go through. Both the main hybrid battery and the new 12 Volt battery have gone dead twice from non use of the vehicle for over 2 months, and also of course myself "cranking the engine" in hopes that it will come back to life. Can someone help me and guide me in the right direction. Thankyou very much, Rick