My car fixed itself??

For the last 2 months I have had a check engine light, and a code 9 from the ECU.

My car battery ran completely out of juice, so i replaced it and now there is no code, and the car is no longer having the problems it was with the old battery.

The timing seems to be perfect again, and it no longer bogs.

I am not complaining, I just don't understand how it happend lol..

probably had a bad cell, dropped the voltage it putting out, caused computer to shit itself.

reseting the ecu (pulling the power) will clear codes from the ecu. sometimes it's just a bad reading that causes the light to turn on. and not a permanent problem.

that's the first thing I do when I get a CEL light, reset the ECU, and see if it comes back, if it goes away I don't worry if it comes back quicky then I worry.

Kun