2008 Prius warning light - what does this one mean?

My 2008 Prius was bumped (fairly lightly) from behind by another vehicle while stopped at a light. No visible damage, and it rode fine afterwards. But there is a red warning light on now that is a picture of a car (no exclamation point in it). My husband is home with the car so that's all I know right now. He did not say it was flashing. Is this a sensor issue with the system for theft deterrence? Something else? I will have it looked at next week when i return home but should I be concerned? Thanks!

 

Thanks! I did find the owners manual online (but thank you for posting it!!). That's why i think it might be the theft immobilizer system, but since I'm not with the car i thought someone might have a firm idea. Maybe it's a sensor, though i don't know if that is costly to fix. The driver of the other car was a student and I'm not anxious to report this and cause him a problem if it's minor. (Also, I forgot to find out if the warning light is flashing, which would be normal; I only know it's red.)

 

Thanks. It's frustrating that I'm not there to try out different solutions. So all I can do is worry. :-(