With no small amount of irony, about a week after I installed the ultra-high-tech Parrot Asteroid Smart, my SVT lit its engine warning light.
I know the sound and feel of my car really well, and it sounded and felt fine. Since a dealer would want $75 just to tell me what's wrong, I figured it was time to invest in an OBD II scanner. This device plugs into the OBD II port that every post-1996 car has, and gives you a code to tell you what's wrong (along with a lot of other data).
But wait! Now you can get a "scanner" that talks to your tablet or smartphone via Bluetooth! Now that's some app awesomeness.