2013 KW T800 def/check engine light, ABS, & TC lights are on

Hi, I’m new to the forum, I’m hoping you guys can figure out what’s wrong with my 2013 kenworth t800. I bought the truck about 4 months ago, and haven’t driven it much. It has 316,000 miles and I think it’s a great truck. It has a 15l cummins isx motor. I recently got surgery so that’s delaying me from starting to work. I run a end dump trailer on my truck. I go now and then to start the truck, and it started giving a check engine light. It says the def needs to be serviced, but the thank is full. The traction control and abs lights are on as well, those where on when I purchased the truck. I need to get rid of all the lights due to scales and check points in california. Thank you all for your time. If you need further info on the truck I will gladly let you all know. Thank you.