While travelling country road (divided highway) cruising at approximately 65 mph (cruise control engaged) the message indicator went "ding" and the check engine light began flashing. I turned on flashers, slowed down and found a commercial driveway into which I could exit and stop off roadway. After turning off ignition I immediately raised the hood and found active fire (flames) to the rear of the intake manifold and forward of the firewall where the wiring harness is located. I instructed my passenger to immediately exit the vehicle. I had bottles of drinking water with us (hot day in Texas) so I took three or four bottles of water and extinguished the flames from both sides of the upper engine. The flames were immediately extinguished indicating no presence of petroleum products fueling the flames. After ensuring that fire was fully extinguished I called a local towing service to come pick us up and drop the Jeep at a local NAPA repair shop. Shop located and ordered a new wiring harness as opposed to trying to repair existing harness. May file a claim with Auto Insurance after repairs are made.