I did try that - the key I used when it happened was a key fob with a dying/dead battery - I thought maybe the XXS was a security feature disabling the car. I tried my other working Fob with a good battery and still no start. I tried locking and unlocking the car, as well as disconnecting the battery.

My owners manual says it should work - but my valet key has never started the car (will just turn it over like the current situation I am in) so I have always assumed there to be a sensor in the fob that talks to the security system.