Please help me! oil service interval light is always full. Not working.

[hitman22]

Hello everyone.

I need your help. I have x5 e53 2005. I changed engine oil and reset oil service then drove 7000km but oil service interval light is full state now. Not reduce. I used this x5 e53, 12years at this time and changed engine oil each after drove 5000-7000km, of course reset also.
The service interval light function was no problem before 11month when I reset after change oil. I changed oil three times and three times reset from at that time. But oil change interval light is no change.
I don't know what is problem. Please help me.