While driving my XC70 2004, the engine will jolt and lose power for a few seconds, then restart itself. The dash lights and gauges, radio, bright lights and turn signals shut down and do not come back on. This only seemed to happen on long trips(over a hundred miles). However, in the last 2 days, it has happened on short in town trips, just after a regular servicing. Last year I had the dealer download some updates, which I thought had cured the problem, until now. If one stops the car and shuts it down, then starts it again, everything will work again, until the next incident. Help.