Here is a list of VW's Self Study Programms (pdf-s) and those related to Phaeton (SSP 270 is a good starting point):
250 - VW Phaeton W12 - Engine Management
270 - VW Phaeton
271 - VW Phaeton - Air Conditioner and Heating
272 - VW Phaeton - Board Net - Part 01 / Part 02
273 - VW Phaeton - Comfort and Security Electronics - Part 01 / Part 02 / Part 03
274 - VW Phaeton - Infotainment System
275 - VW Phaeton - Air Suspension with Regulated Damping - Part 01 / Part 02 / Part 03
276 - VW Phaeton - Automatic Distance Rregulation (ADR)
277 - VW Phaeton - Chassis
280 - VW Phaeton - Auxiliary heater Thermo TOP C and supplementary heater Thermo TOP Z - Part 01 / Part 02