I had my car taken in once the check engine light came on. It needed a PCV valve replacement and an oil change. Both were done by my mechanic (who used to do my bmw). The power steering fluid was empty too so he topped it up with his own one.

When I went to collect the car and drove it around, I noticed that the servotronic does not work. The power steering does, the servotronic does not though.

Spoke to the mechanic about it. He said he used a hydraulic mineral power steering fluid which is what the car requires. Something definitely happened while he had the car to replace the PCV valve + oil change. Either topping it up, switching it off through the fuse (though he's adamant he didn't touch it) or the vag-com might have altered or switched it off (is this a possibility)?

Spoke to another VW/Audi technician. He suggests that we flush the fluid and refill it. See if that works. No guarantee and it'll cost $120.

Spoke to Audi and they said "if you use anything else other than Audi then it could mess up the pump and the steering rack requiring a whole rebuild".