My 2006 saturn vue power steering doesn't work periodically what can it be

Hello, your Vue is equipped with electric power steering, which means a series of sensors and a control module and motor provide power assist to your steering gear. If it is intermittently not working, you'll have to perform needed diagnostic testing to find out why. This requires a Saturn compatible diagnostic computer with software that can diagnose chassis concerns -- not just engine performance concerns. I'd also say you'd need a Saturn / GM experienced / trained technician to check this out for you. It is not a simple system and requires hands on checking. It is also not an inexpensive concern to repair, unfortunately. Good luck!