The other day i was driving my 2001 Infiniti QX4 on cruise control and all of a sudden the cruise went off and the car didnt shift to 4th gear. I stopped switched it off and waited a few seconds and turned it back on and then i got a something that lighted that said " AT CHECK'" could some1 plz help me?????

you have a trans code. Have it checked at the dealer. Simple checks you could do is a fluid level check with the car idling in park. Make sure its at the right level. If that looks ok you need to hit the dealer your not going into lock up. Was the O/D light flashing when the cruise shut down? That is a definite indication of a trans control problem. Could be the speed sensor in the dash or the unified meter as a whole.