automatic scenic 1.6

Hi everyone i have a 1998 scenic 1.6 auto,it has recently started putting up the engine managment light which causes it to go into limp mode,this results in loss of power and the autobox only responding to drive not any of the other forward gears,i have had it scanned which showed up no permenant rpm live feed but the car still starts and drives. Sometimes after stopping and restarting the light stays off and everything reverts back to normal,any ideas anyone????:confused: