a yellow light shaped like a horseshoe with an exclamation mark in it

This is your tire pressure,check your tires.

You have a tire going flat. That symbol is a cross section of a tire.

If a wheel without a pressure monitor is mounted on the car the computer goes nuts. Then a nice spot of black tape performs wonders. If you can't feel a very low pressure or don't check pressure monthly then shame on you anyway! Yes, you gather that I do NOT believe in TPMS. One reason is that it only reads DIFFERENCES among tires, and therefore doesn't tell you to compensate for falling temps in the fall and winter, where monitoring pressure and adding air is important. Remember, tire pressure drops about 1 psi for each 10F temp drop. So 80F to 20F is -6psi,,,plus whatever you squeeze out naturally. Sometimes nannies have to be outsmarted....