It depends- it could be part of the petrol tank evaporative control system---- OR it could be part of the aircon filtration system? Need to know the age/model of the car and maybe the part no of the spare part listed
It's for my car as in my Signature, I've just been looking at my Servive Book that the dealer stamps when the service is done.
It has a list of things to tick to say if it's been changed eg - Spark Plugs, Air Filter, Engine Oil & Filter etc & Activated Charcoal Filter is there.
I asked this question and was told that I would know it as a pollen filter although I have read threads on here that indicate that if you have 'climate control' you may have extra charcoal filters behind the glove box. P.S. I do not have an activated charcoal filter which means they were going to charge me £120 for something that I do not have and so do not need ...................... MB?