Turn ignition on, engine off and shut all doors. Press the step button until 0 miles to service is displayed. Press and hold reset until display changes to normal service interval.
Move through the overhead display to where it says perform service. Hold down the Reset button for a few seconds and it will reset to "3,000 miles to service"
You will have to get the engine scanned and the necessary repairs made. Then the check engine light can be cleared. Just to clear the light without the repair will result in the light comming back...