Engine Light ON??

Hello Everyone..
I recently had a test drive on a 1999 I30 with 99K miles on it..
Planning to buy it..
During my test drive, I had noticed the Engine light was ON and asked the dealer to find the reason and fix it..
The next day the light was fixed and when I inquired about the reason, he said that the light had turned ON because the car was approaching 100K miles on it... Sounded fishy to me...
Can someone please tell me if the dealers theory is right or should I get the engine tested at a different place.
This is my first car... so will realy appreciate help...
Thanks..

the dealers not right that light will only come on for a problem and will flash if it has a misfire there is no interval