engine management light

[lampardluver]

Since I've started doing longer journey to work, the engine management light comes on as I'm driving. It only stays on for about 10-20 seconds, then goes off again. But it is getting more frequent by the day.
The car is running well (as well as a 11 yr old car does!!) so not sure of the problem.
Anyway car is at garage for check - what does this involve and what could the faults be. Also could this be an expensive job????

[LostSheep]

What car is it??

[lampardluver]

Vauxhall Corsa 1.2 P reg