It is interesting to see in the Tech Service Bulletin 48 for curing the idle surge, that they have the following "CAUTION:
• Connect a battery charger to the vehicle battery.
If the 12V battery voltage drops during reprogramming, the ECM may be damaged.
• Be sure to turn OFF all vehicle electrical loads.
If a vehicle electrical load remains ON, the ECM may be damaged.
• For ECM reprogramming, the C-III MUST be connected to the VI using the USB cable.
• Be sure to connect the AC Adapter.
If the C-III battery voltage drops during reprogramming, the process will be interrupted and the ECM will be damaged."

Has anyone had a "damaged" ECM? I worry about all electronics with the weak starting that i have after the car sits for a day or so.

 

never had an issue with my 09. heard its mostly an 08 issue.

 

I just had the second battery installed after they had the car for a week and could not find a problem. I googled the model number of the Infinity batteries that they put in, and you will find in the forum many people having the same problem. They talk about the batteries being bad. saying things like the Bose amp in the car is dwawing down the battery. Do they have battery savers in these G37 coupe's. The dealer told me they only have problems with the S models, which i have.

 

There are known electrical issues with G37. My car had a dead battery after 8 months with 8k miles.
My dealership suggested an oversized battery because the alternator is not recharging the battery sufficiently
Good luck