I overlooked the part where your engine light came on. Your tractor is large enough (over 25 horsepower) and new enough (newer than 2014) that there is probably a lot of computer control. You will probably have to contact the dealer to read the computer and see how things are configured. In all likelihood you have a diesel particulate filter and it may not be working or regenerating correctly.
Thanks. Will check out.Dirty injectors and wrong fuel injection timing do the same. Run a compression test first. Also make sure that nobody added gas instead of diesel to the tank.