Hadn't run the REX for quite a while so decided to fire it up and run out some gas the other day. Shortly after the REX started the Check Engine light came on. Scanned it with my "Torque" app and it shows P0440 "Evaporative Emission Control System". I then scanned using the "BimmerLink" app and it shows a code 106004 "Tank Ventilation Valve Malfunction". Wondering if anybody has gotten this code before and if it actually is the tank ventilation valve? And if so, is this a reasonable DIY job for a moderatly mechanically inclined person?