Re: 147 Error Message
Mine did that and it turned out to be the turbo boost sensor, the accelerator body and the exhaust gas recirculation valve.
Every time one of those were changed, the error messages became less and less frequent until I haven't seen them again (well, it's been ok for 4 weeks now).
I wouldn't go buying a new battery straight off. Get it checked out first. Kwik Fit do a free battery test. The trouble with modern cars is that it could be any of the hundreds of sensors, wires or connectors and it's impossible to tell which one's nackered.
The 147 is supposed to store error codes so you can get them read by a diagnostic machine. Trouble is, if it's an intermittent fault next time you start the car and the start-up checks are clean, the 147 wipes its memory and no-one can tell what's up with it. As soon as the light comes on, get it staright to the main dealer without turning the engine off and get them to read the fault code for you then and there.
Hope that helps, I've had a nightmare with these Motor Control System Failures since I bought the car but touch wood, she's behaving now.