[talkingcars]

It stores excess petrol vapour from the fuel tank and injection system and releases it into the inlet manifold to be burnt in the engine.

One of the most common reasons for excess vapour is over filling the fuel tank, never fill it beyond the first click on the pump.

Might be worth unplugging the electrical plug on the inlet manifold that opens the purge valve to double check that it is this that is clicking - just follow the hose from the canister to the manifold and the plug is next to it.

If it is the valve don't worry (except it is wasting your petrol), it's doing what it's ment to do.