Lose Power Steering problems of the 2008 Lexus Rx400h

While driving on a city street, I lost power steering completely. P/s and brake dash lights came on along with "service hybrid system" and "service awd system". After a few more miles the vehicle lost complete propulsion power and I was forced to pull out of traffic. I turned off the vehicle and it started fine with no power steering. I made the next mile to the dealership. They replaced the ecu that had shorted out due to a bad steering rack. I am not sure why the electronic steering mechanism would cause complete loss of power from the engine/hybrid system?.