my E430 will not go into gear after it warms up.

It is more common for the trans to have shifting issues when cold and smooth out after warming up, or for the trans to start slipping after warming up. If the indicator is inoperative after the trans is warm but normal when it is cold this could be an elctrical issue with a sensor or switch. The only way to be more specific would be to get a compatible diagnostic tool on the vehicle to look at transmission sensor outputs.