BMW Repair: Exhaust Emittion light is on, bmw 316i, correct software

Question
I have a BMW 316i SE Limo type, Manufactured March 2000. The Exhaust Emittion warning light has comes on and off. Can you please explain the reason for this.  

Answer
Nelson, You need to have the fault read out to see what fault has been stored in the control modules memory that would cause the Check engine (or service engine soon) light on. You can go to the dealership or a service shop that has the correct software to read out the fault memories.
-Evan