Not your Check Engine light but if you have anti-lock brakes, you must have all four tires the same size or the mismatch will be detected, turn on the yellow ABS warning light, and turn the system off.
Look on the door sticker to see the recommended tire sizes. You are right about the speedometer. It's reading is based on how fast the wheels are turning, not how much distance has been covered.
Wednesday, June 20th, 2012 AT 5:34 AM