code shadowed 50 (080) power sply undervoltage what does it mean?

[shawn01]

i have this come up on my scanner and when i try to clear it still stays in the shadowed section , will this cause any harm ? my check engine light doesnt light up thanks

[Icer006]

when was the last time you replaced your battery?

[shawn01]

replaced it about a year and a half ago but i do have subs and a amp running through my bmw aswell, but nothing pops up with the check engine light.