So the other day noticed a huge amount of white smoke when starting the car cold, and a very high idle (1500rpm) when in neutral or park.
Read codes and got this
P2187 P2189 and P0507 - some google-fu says it's most likely a torn AOS diaphragm, located under the black cap here. Also checked oil level - was very very low!
Apparently Porsche won't sell you the 50c diaphragm, wanting to sell you the entire valve cover instead for a kidney and liver.
Anyway, I removed the plastic cover and found a very obviously broken crankcase breather hose, which has a connection to the AOS as well. Broken hose = no vacuum = defective AOS operation.
Also removed the AOS cap after a great deal of swearing, and found the diaphragm was sound - removed it from the cap and checked it inside and out.
Anyway, found a seller on Aliexpress who would send me a new cap, diaphragm, plastic mount and spring for just USD $30 delivered - bargain! And only took 2 weeks to Melbourne.
To repair the broken crankcase breather hose, I'm not going to spend $100s on another thin plastic hose that'll break - instead, I removed the piping from the end connectors, grabbed some 16mm PEX pipe from Bunnings and used a little bit of gasket maker to seal the ends - this will never break.
Replaced the AOS with the Aliexpress one, replaced the crankcase hose and engine cover. All is good - no white smoke, plenty of power, and we're back in action again for about $50!