Component Location - E90
On the E90, both the active reservoir as well as the passive reservoir are located under the luggage compartment floor with the active reservoir being the lowermost of both.
The fillers are located on the left-hand side behind the rear wheel where they are accessible through an opening in the bumper panel. The fillers are arranged in the same way as the reservoirs, i.e. the lower most is the filler for the active reservoir. The transfer unit and the filter are located behind the filler.