Just to confirm it can be done. I installed a European parking heater (Toureg version) in my US Spec 2011 CTT. Purchased the unit with piping, muffler and mounting bracket on EBay (German EBay to be exact). It also contained the recirc pump and the magnetic isolation valve. The one I purchased was only for 2-zone heating and not 4-zone that I have in car, so needed to buy a few additional y-pipes. I used an Audi parking heater fuel pump and a generic fuel standpipe for the gas tank. I also installed a new console switch (although I believe you can get into the auxiliary heater menu on the instrument console screen without it). I generally followed this thread for the same work on a Toureg. As with all DIYs posted, I take no responsibility for any damage or complications this causes you or your vehicle. This is posted for informational purposes only.
(Since I am a new poster, I can't post a link so you will need to search for "2015-canadian-touareg-7p-webasto-parking-heater-retrofit.285929")
A good place for parts numbers/diagrams for this system (albeit for the Toureg) is at:
For the two CAN bus wires, you need to be on the correct CAN bus. I tried to connect to the OBD port CAN bus where my remote starter connects (see remote starter instructions below), but that did not work (aux heater did not show up in PIWIS). I researched the various CAN bus groups in the PIWIS wiring diagrams and determined it needs to be on the bus with the PCM and the most convenient spot I found to connect was actually to the dashboard compass (easier to pop out than the PCM head unit), so I spliced it there and all worked.
Then, when you get to the coding portion, I used PIWIS II to do the following:
Highlight ALL control units and go into coding tab.
Select Code Using MCR rules
Change in two places the option for country coding to B00 (Not specified) and B0A (components without country specific rules) respectively - I am not sure whether this is absolutely necessary but my previous direct coding (not using MCR rules) without it did not work. I am only surmising that the country coding may play into the MCR rules and prevent activation of the parking heater. But I may be wrong. I just don't really feel like changing it back to test since all is working fine.
Change parking heater option from 9M0 to 9M9 (assuming you will add a T90 remote control at some point)
Noteworthy part numbers for the work:
Parking heater hoses for (4) zone (Porsche and VW numbers):
95857291210 (10) $107 (10) 7P0819912C
95857298100 (19) $12 (1) 7P0815981
95557278400 (20) $13 (4) 7L0815985
95857292500 (21) $96 (2) 7P0819925B
Console switch w/ parking heater and windscreen heat (I retrofitted the heated windshield as well).
95861313800 (without windscreen heating should be 95861313600)
N10451404 (bolt) x2
N90263104 (frame nut) x2
N01508210 (nut) x1
Because I changed the country coding, I had to then manually code the PCM tuner to use US standards (otherwise AM radio did not work). I also had to reset the dashboard display units to US units (this can be done right in the instrument cluster vehicle information screens).
PIWIS has the line filling (priming) function as well for the initial fill of the heater fuel line. The first Webasto T90 I ordered was inadvertently a LIN bus model (for 2015+ cars) and I am in the process of installing a W-bus version. Until that is in, I can confirm the timer and instant use functions of the heater work great. I set the timer for 10 minutes before I am getting in the car in the morning and it is toasty. I also have remote start in the car, but this is kinder to the engine and allows quicker and more efficient heating of the cabin for frost melt, etc.
My next step is to install an auxiliary relay bridge (using a VIPER alarm module) between my remote start and the controller to allow cell phone activation of the parking heater and the heated windhshield, which I retrofitted at the same time.
If you are interested in installing a remote start, I asked a few installers and got about a 50:50 response that went from "don't install one because it will mess with your OBD communications port and cause problems" to "no issues we install them all the time for the local dealership". I decided since I was bored, to try it myself and have absolutely no problems with it. Great for summer AC start-up. You will at least need to pay an installer to flash the module with the Cayenne-specific firmware, which cost me $80. Otherwise, buy a DEI DBALL2 module and I followed these instructions to the letter
(Again, can't post a link
so search for "dball-dball2-toki02-rsr_en_ig_th20151020.pdf")
The hardest part of this installation was actually determining which wire was the brake bypass wire on the passenger side. There are probably a dozen black w/ red stripe wires in that bundle. Using a shirt pin, I stuck through each insulation and tested voltage as they said. A few did go from 0 to 12V and I thought that was correct, but no - keep looking until you find the one that has some voltage (like the 0.6V they show) and then goes to 12V when brake is depressed. I swear this was the last one in the bundle I tested - that's how I know there are about a dozen.