DAF CF 85 460 Prime Move/Tractor 2016 "Engine Warning?

DAF CF 85 460 Prime Move/Tractor 2016 approx 315000 kms - Randomly Flashing "Engine Warning" every now and then and fan kicks in full blast.

It's the AdBlue engine. There was a notification sound and flashing "Engine Warning" came up on the dash. As soon as it comes up the fan kicks in full blast. It lasted a few seconds at a time, maybe 5 to 30 seconds. Sometimes it happened a few times in a span of few minutes and go away for days or weeks. Sometimes only once and go away. When the coolant temp gone down it stopped. Noted that it did not overheat. I noticed the following. - Load or no load doesn't matter. Sometimes I was towing empty container and that happened. Sometimes fully loaded. - A few times it happened after I used an auxiliary brake for a while down the hill. A few times on the flat road. A few times up the hill. - Oil and Coolant at Max level. - When that happened, coolant temp gauge is in the middle or less. Sometime only 25% and it went down even further. - Truck still pulling as it should be. - It almost feels like the truck sensed some extra heat somewhere and try to cool it down... I was told by the fellow drivers who drive DAF and they reckoned that happened from times to times with the other trucks as well and it could have caused by old trailer losing air here and there. It sounds weird but I don't know much about DAF. Please assist. Thank you in advance.