Common fault with Mitsi's - means the electronics havn't succeeded in taking it out of 4x4.
Make sure the 4x4 selector is in the 2 high position.
Drive forward quite sharply for a short distance.
Put it in reverse and dive backwards quite sharply for a few yards.
Drive forwards again and it should clear after a short while.
If it doesn't you may have a major gearbox problem and it would be best to look for another.