hi,does any one no what the black round canister is that sits on the right hand side of the car by the head light is as mine is broken?

 

Carbon canister

 

what does it do?

 

Its something to do with the excess fuel being returned to the tank,But im not sure exactly how it works,I know many people have removed them.

 

They are naughty peeps!
Construction And Use and all that stuff.

 

what?

 

It's part of the system to stop fuel vapour from the fuel tank being vented to atmosphere. The carbon in the canister absorbs the vapour from the tank when the engine is off. The ECU then controls a valve to release the vapours into the engine when the engine is running and when the running conditions are such that the vapour will not cause excessive emissions.
Just as you shouldn't vent engine breathers to atmosphere now.
Although some do.