The engine management lamp comes on when a fault develops in the engine fuel, ignition or emission systems. At this stage its impossible to tell why, but a 'fault code' is stored in the car's on board computer, and this can be interrogated by any garage with suitable diagnostic equipment. They can then recommend a repair, and turn the light back off for you. Take a tip....if you let a fault continue there is a chance that the catalytic converter could be damaged - quite expensive.
John, January 2008