Undo the two screws to remove the lower facia panel from above the passenger's footwell. Next, undo the four screws, remove the cover, and pull the pollen filter downwards from the heater housing. There are two possible locations in the heater housing for the pollen filter; standard filters slide up into the narrower slot, while multi-filters, used in vehicles with an air quality sensor, slide into the wider slot. It is important that both a standard and multi-filter are not fitted together. After sliding the appropriate filter into place, refit the cover and securely tighten the retaining screws before refitting the lower facia panel.