Last update - now driven it over a thousand miles, never recurred. I'm thinking it must have been some kind of critter that got in at the first stop and got out at the second.

 

I had the same error come up last summer - got the error and the engine turned off. But it wouldn't restart. Thought it was the battery. I had it towed to the dealer, and they told me it was actually the fuel pump that went out. That was a 6-week repair. Luckily I had a loaner for that time, but the fuel pump failure is common for these cars (mine is a '22 LE) and the pumps are backordered. Hope it's not the same issue for you. Thought it was weird that the error it gave me was the charging system error since it wasn't related to that at all.

 

If your CEL is ever flashing, you should not drive it it anywhere. You’re likely to make things worse if you do. Unless the ECU has been reset, with a code reader or by disconnecting the battery, you should be able to find any codes in the ECU history. Don’t start replacing parts unless you have done some diagnostic work to determine the culprit and confirmed the part has malfunctioned. Coilpacks can malfunction but they aren’t a maintenance item, so there is no reason to replace them unless you know it’s bad. It’s very unlikely that all 3 would malfunction at the same time. If you ever have a flashing CEL u should park it and try to get lit towed somewhere where it can be worked on. The CEL going away doesn’t mean the problem is solved, it could come back on anytime, so I would try to figure out before you get stranded somewhere or worse.