Hi I have a 2015 freightliner m2 with a Detroit diesel engine. It has the idle cutoff program where it shuts down after 20 minutes. Usually when it gets to hot out or cold though I've been able to chalk my wheels and turn off the brake and it will keep idling to keep the cabin comfortable. Well now it wont even do that the truck shuts down after about 30 minutes and the check engine light comes on. It starts back up with no problems and will continue to idle for another half hour or so but then does it again. Do any of you guys might know what is going on here? Is it time for a mechanic? Is it time for a new engine?