This is an indication that there is a fault present within this system. These require specialised computer scanning and repair. You should be aware that specific faults do relate to warrant of fitness and safety issues.
Engine light stays on
When Engine light stays on for eg. running rough, hard starting, miss-firing.
SRS/Airbag light stays on
Airbag system will not operate while this light is illuminated. In the event of a vehicle accident/crash - the Airbag system will not deploy.
ABS light stays on
ABS system will not operate while this light is illuminated. Car brakes will lock up during heavy breaking while the system remains inoperative.
Battery light stays on
eg. hard starting, overcharging, undercharging, no charge or battery fault.