If you car has run-flat tires it has tire monitor system, believe it was also an option for cars that didn't have the run-flat tires. The yellow warning looks like a flat tire with "!" in the center. THis indicates that one or more of the tires doesn't have the correct air pressure in them. If the car has the tire air pressure monitor system, there should be a button just under the little compartment in front of the shifter that will/should re-set the warning light (provided that one or more of the wheel sensors isn't bad). The sensors in the wheels do go bad, so if air pressure in all 4 tires is correct and the light can not be re-set, have the codes read, the codes will tell you which wheel sensor(s) are bad.