im on a similar thing for my caddy. There was a High pressure sensor G65 fault on VCDS. i have had it regassed at kwik fit but still didnt work and the error came back after clearing it.
i ordered a new sensor from VW @ just less than £50 and fitted it myself. The error cleared and has not come back, just LOW PRESSURE, so Its in at VW now getting regassed. Picking it up later today so hopefully just sensor was fooked.