2012 Jeep Grand Cherokee 3.6L crank won't start
 

I have replace the ecm and the throttle body position sensor after it shut off going down the road. I haven't got it started yet. It throws different codes every time I put it on the scanner. The battery is losing voltage every time I turn the ignition switch. I have had to have the battery recharged twice now. It dies after attempting to start the Jeep just a few times. The battery is good was checked every time I took it in to be charged. I am lost as to what to do next. I really need this vehicle on the road. It is a daily driver. Here are some of the latest codes u1191, lost communication with upper switch bank 1. More codes referring to the lost of voltage.

This is the regular 1984-2001 Cherokee forum. Have you checked the ground cables? The regular 2014+ Cherokees have a known issue where the ground cable that runs from the battery to the trans to the frame, rots out between the frame and trans. This bad battery connection causes all kinds of strange error messages because some computers crash while cranking due to the low voltage.