Check engine light stays on one day and off the next on 2003 Dodge Ram 2500

Why does my check engine light stay on one day then the next day its off? This happens every other day.

Asked by for the 2003 Dodge Ram 2500
The check engine light can come on for hundreds of reasons, you'll need to get the diagnostic codes checked and then you'll have a better idea of why the light is coming on.