Check Engine Light On problems of the 2005 Jaguar XJ

Driving on the highway going about 70mph, not accelerating nor coasting, just maintaining speed. The engine basically shut down, and I had to pull onto the shoulder, it was very dangerous and frankly, it scared me. Engine light on, as well as "engine systems fault, parkbrake fault, dsc not available" showing up on the dash. I restarted the car about 4-5 times and it eventually started. I am assuming, this has happened numerous times over the past several years and no-one seems to have any idea what is causing it. It happens on busy highways and local street driving. This is a very dangerous situation. The cars engine could cut out at a moments notice and leave you in a very dangerous situation!.