I've read numerous reports of unexplained engine warning light operation on diesel Jeep Grand Cherokees, so I thought I would share my experience of this issue. On several random occasions my 2013 model showed the engine warning light symbol, which would remain on for some time before going off. It was disturbing enough for me to go to my dealer to have it checked out. No real answer was found until I checked the owner's manual and discovered that the warning light can be triggered by failing to tighten the fuel filler cap more than three or more clicks. At no time did the Jeep service people mention this as a possible cause. I have not experienced this problem again, except when I forgot to tighten the filler cap correctly. I hope this helps other owners.
It's something worth checking for anyone who is having the warning light come on without explanation. Could be a simple fix.