are you sure it was a flow issue to the evap canister? the only fault i think
that can set for the evap system would be a minor or major tank leak detected.
this car has a system called DMTL which pressurizes the fuel tank and
measures the speed of a reed switch which is connected to the pressurizing
pump (are you with me?) the speed of the reed switch is measured, and the
control unit knows that if the reed switch slows down, that the tank is
sealed because its building pressure. if the switch is going faster,
obviously, it knows that there is a leak.
now this may not even be related to your problem. i think the other thing you
may have is a bad secondary air system. there is an electric pump in the R/F
under your hood that injects fresh air after start up. there is a valve to
let the air into the exhaust which is controlled by vaccum. these vavles go
bad frequently and throw a code for no secondary air flow. either that or the
pump just stopped working and there is no air going in because of that. i'll
check that code number at work tomorrow if i remember (i work at BMW) and try
to get back with some more ideas.