We don't have ESS, but just dealt with a failing battery. In our experience, when the car battery is dying, it acts like a petulant teenager, hurting all sorts of insults at you. That's perhaps an extreme analogy, but we had everything from "service shifter" to "reverse baking unavailable" to messages about the doors and kick sensors (and we don't even have kick sensors). It would even kill the lights on the shifter, leaving the selected gear dim, making it a bit of a guessing game to shift from memory and hope you were not in drive when you wanted reverse - use the information center screen to help in this scenario.
Replacing the battery is easy, or as easy as anything is to do under the hood (where one has to remove three components or cross braces to just get at something!) As we are out of warranty, we got ours at Costco and it took about 30 minutes or less to do.
2017 Pacifica Touring L (gas) w/tow. April 2016 build.