Not many updates so far, but the dreaded diesel maintenence is starting to creep in.
Diesel Aftertreatment: During some long trips, P20EE set which indicates a low efficiency for the underfloor SCR (post DPF), as well as some NOX Sensor 2 DTCs. Using the PorII ScanTool you can read DME variables, so checking out the NOX Sensor 2 readings showed this sensor is faulty (reading max NOX value). After fixing the coolant leak, will be taking this to the dealer to fix under the extended emissions warranty which should most certainly be covered.
Oil Leaks: sounds like some TDIs leak (a lot) and some don't, ours leaks! We were able to finally find a dealer that would honor, or even attempt to honor, the emissions warranty for the oil leak. They elected NOT to pull the engine and reseal the entire engine, and only replace the front main seal. I've since changed the oil, replaced the drain plug with the revised part number Porsche Genuine, and checked again for leaks. It appears the rear main seal is leaking, as well as the valve covers. I'll likely try to get this same dealer to warranty again, as it runs out in Dec this year.
Coolant Leaks: I noticed a coolant smell and sure enough the coolant level sensor has been indicating low. I debated whether or not to get the dealer to fix this, based on my experience I doubt they would, so I am attempting to fix on my own. A common leak on these is a regulator valve under the intake manifold, or the engine oil cooler, or the assortment of gaskets/seals in that area. This means the coolant needs to be slightly drained and refilled, and a vacuum filler is required for this system, so I bought an Airlift UView filler. More to come on this attempt, parts are only about $40 for all gaskets, $80 for the regulator valve, but $300+ for the oil cooler.
https://rennlist.com/forums/cayenne-958-2011-2018/1165059-cayenne-diesel-coolant-leak-need-help.html
https://www.cpsproducts.com/product-details/550000/
EGR Fouling: Especially after the dieselgate flash, there is a propensity for buildup of carbon in the intact tract post-EGR cooler exit. There are two parts that foul up, the intake pipe and intake manifold. The intake pipe is easy to clean and remove, while the manifold not so much. Since I'll have the manifold off already, I'll clean both. A lot of rennlist users reported improved drivability and turbo response after cleaning, and seeing some of the photos I can believe it.
https://rennlist.com/forums/cayenne-958-2011-2018/1152733-egr-is-the-devil-bobby-boucher-diesel-egr-that-is.html
Some good 3.0L TDI engine overview docs here:
http://www.volkspage.net/technik/ssp/ssp/SSP_350.pdf
https://pics.tdiclub.com/data/517/840193_3_0_TDI.pdf
For FSMs, alldata is one option and not so legally are the full Porsche PDFs (10,000 pages!) which can be found at certain illegitimate sources.