[Smart Bob]

My wife's 09 Pure with just under 13k, threw a CEL today. The code was P2178, system too rich. I erased the code, drove the vehicle & everything is back to normal.
Prior to the CEL coming on, the car was shifting abruptly and harsh. It didn't turn on the CEL until the end of the trip, which was about 30 minutes. The car also seemed to hiccup slightly around 70 mph.
About a month ago, I had the harsh shifting symptoms, but no CEL. I disconnected the battery for 30 min. & after reconnecting, everything was fine.
Has anyone had any experience with the code? I kind of suspect the evaporative emission control system. Please note that when I refuel, I fill on automatic and once the nozzle shuts off, I do not top off.
Your input would be appreciated.
Thank you,
Bob

 

[rfernatt]

My '08 has thrown that code twice in the 70K miles I've owned it, but the car seemed to be running fine each time so I cleared it and it stayed off. For me, it just seems to be a sensor that is a little twitchy and gets tripped up every once in a while.

 

[Smart Bob]

I drove the car today. No codes and no rough shifting. The rough shifting bothers me more then the code. I am wondering if they are related as the rough shifting has taken place before the CEL comes on?