Engine Management Light On

[Mark060457]

Hi Guys

Just had the engine management light come on,Cannot get the car into the rover garage till tomorrow to get it sorted,but lucky my next door neighour has a code reader,and it is showing that the

Evaporative emission system purge control value circuit shorted,

What i would like to know is this an easy job or is it going to cost mega money,and in laymans terms what does it mean,and what does it do,

Look forward to your replies

Mark