How to clear low oil warning sign
 

Please does anyone know how to reset or clear off a low oil warning sign off a 2005 C5500, 6.6L diesel truck? Serviced my truck and only drove it for 900 miles before the low oil light came on, checked the oil and it was low and I added 2 quart and it's on normal now but light won't go away.

might need a new sensor, or the wiring on it is dmg. its located on the side of the oil pan.