Welcome to the forum. Would help if you gave the year and trim level as well. You need to get your hands on an OBD scanner to find out if there are any stored or pending codes to help you diagnose the problem further. But considering you disconnected the battery any non-permanent codes will be erased from memory. Another thing to check is the condition of the battery, if it has a bad cell and voltage is low it can create problems on the can bus.

 

Update : Thank you for everyone’s replies . Ended up being the transmission valve . Plus fuses were being burned every time they were trying to reset . Replaced transmission valve at the dealership . Problem solved and it’s running great so far 😅

 

He did. 2014 Limited. +1 on the battery check. Also remove the battery cables and short them together for a few moments to reset the computers and then see if the issue clears.

 

Doh, I did not pay attention to the post title. Is it 845re or the 8HP70?

 

Actually might be the shift mechanism. 2014s had a flakey shift by wire module that would not let it shift out of park. Granted different failure mode but the fact there is a TSB about the SBW would make me suspect it first. But old batteries cause just as many problems.

 

I dealt with an issue similar.
I exposed the bottom of the electronic dial shifter and disconnected the power source for a few, checked the pins and harness for defects before plugging back in.
My problem went away.

 

The price will be your surprise of the day. Surprise!!!! Just take it in but be sure you have a grand in the bank to cover it.