Power steering randomly turns on and off

[S4Kev]

I have a 2008 S4 with 72000 miles, i bought it from Copart as a total loss and had it repaired to be road worthy. I have been driving it for a couple of days with no problems but last night, as i went to make a u-turn my power steering randomly turned off but i continued to drive because i was almost at my destination. I had to turn with both hands and it took a lot of force. I shut the car off at my destination and turned it back on about 5 minutes later and it was fine, i thought maybe the computer just messed up so i didn't think anything of it but after a mile or two it shut off again. Ever since then it will randomly come on when i least expect it. I have a full reservoir, the pump is making no noises and i have no idea what it could be. Anything will help. Thanks

[pu911]

These have a speed sensitive power steering system- had same problem with a 2005 S6, something in ABS computer if I remember correctly

[S4Newbie]

Check the fuse for the servtronic system, it's in the fuse box by the driver door!

[AudiMat]

I had this exact same problem with mine when I bought it. I thought it was the servotronic relay cutting in and out but it ended up being a power steering line. It was bizarre, when I drove the car home after picking it up (450 miles) it would seem to randomly cut on me when I was slowing down into rest stops, and then be fine when I would restart the car. Then a few days later I was headed home from work and suddenly I lost all my power steering fluid and one of the main lines had completely split in two.