NHTSA campaign number 18V740000 was issued last fall, but we didn't get the notification until early this year. Blame the delay on the weird ownership situation of long-term vehicles. NHTSA's basic description is short. "After the vehicle has been operating in PHEV propulsion mode, the gas-fueled engine may not restart properly resulting in unburned fuel entering the exhaust catalyst." Basically, the engine may not restart correctly after running in EV mode, and the fuel being fed to the engine could make its way past the exhaust manifold to the catalytic converters and ignite, possibly starting a fire. Obviously, that's bad.
We scheduled a visit to the dealer as soon as we got the news. Chrysler's fix is to update the computer, visually inspect the cats and replace them if needed. We hadn't noticed any issues with the Pacifica's powertrain, and the inspection came back clean, so our Pacifica was back in our hands in a few hours. The service sheet says the left and right cats were inspected by borescope and the powertrain control module was updated. All in, the Pacifica was out of our hands for about half a day.