How to reset the pin code
 

My friend's car will not start even with a new battery he put in yestoday, the engine light flashed. Somebody told him that it will only signal no code until he has been able to start the vehicle and let the computer run though it's checks. When his removed the old battery he reset all the stored codes. The Maxivideo MV301 was recommended to us, but I want to know, for this, will a code scanner help???