why code p2544 on Range Rover

Question

Every time I want to start my Range Rover it says something about the transmission and when I check to see if there is any codes it shows P2544 but no check engine light is on and sometimes it starts and sometimes it doesn't.
I haven't change the oil yet and I think I'm about 8,000 miles over my 10,000 oil change time... could this have anything to do with it ? Please my car is an automatic not manual, I've never need to add any transmission oil to this type of car righy