All three turn on for a variety of different reasons. As Icedragon said you need to have the codes pulled from the ECU to see what is causing it to be set off. Most Autozone/O'Rielly's/Pep Boys will do it for free.
Agreed on having the codes checked. I had a P0041 code for the evap canister malfunctioning, and also a P0012 code for a bad solenoid causing my terrible threes dash lights. The evap was beyond my knowledge of car repairs, so had a mechanic take care of it. Dealer wanted over $1000, so got it done at a mechanic down the road for $600 part and labor.
VSC and Trac Off only is the steering sensor needing to be re-calibrated, just did this last week. But with the check engine light on it could be a multitude of things. All three normally turn on when there are any engine codes thrown.