Similar events unfolding for me too. Bought my 2018 60-days ago and the start/stop pretty much was always "charging" (worked a couple times after some 3 hr trips). Drove it 4 days ago and CEL came on with the message start/stop needs servicing. I went ahead and replaced the AUX14 battery for the ESS and pulled the CEL code at Autozone. Code was P0302 "Cylinder #2 misfire". The new battery didn't resolve the problem, still had a very rough idle, loss of power and CEL kept blinking. I took it to the Chevrolet dealer that sold me the van and holds a 90-day warranty. After they pulled the same code (and no further diagnosis), they said a Chrysler dealer needs to fix it. They're claiming it'll be covered by Chrysler's powertrain warranty, I reckon its ignition system related and want it repaired under the more comprehensive 90-day warranty.
