SSN is not a pleasant feeling about your purchase...trust me, I know. Back in Oct-Nov 2013, a fix came out that virtually removed the issue. It seems that now, SSN is a result of an actual failure. There are a few options.
-Call your dealer and explain the situation. See if they have an idea of what to do. They'll probably ask you to bring it in; however, unless they know what to do, they are just going to scratch their head and stare at it.
-Take it in anyway. Have the issue recorded. If they cannot fix the issue, the Lemon Law, if your state has one, will typically reduce your buy-back by a percentage determined by the miles driven before the first occurrence of the issue.
-Wait for it to fail. And when it does, leave the car on. Do not try to restart the car. Call the tow-truck to take it in and have the dealer look at it in its failed state. They might not be able to determine anything, but it is worth a shot.
Call around and find a dealer who is relatively experienced with the FFE. Could make a difference on whether they can find the issue. Although this is a rare thing now, there have been 2 causes...either cabling, or a bad battery.
By the way, it doesn't seem to matter if you are local driving or freeway driving....but who knows, you're situation could be different.
Good luck.