Isn't this part of the evaporation system for emissions control?
If so it is probably monitored by your engine management system. Which system do you have?
My 2002 plus8 has Gems management that does this.
I did once get the warning light on and my OBD analyser showed a evap fault linked to the cannister.
It cleared without issue and has not come back. Probably caused by me and over enthusiastic throttle when cold!
Try checking Gomog site for info.
