X-MOB03

I just installed my nitrous kit and one thing about it is that it is throwing a code 2 wich is the 02 sensor, either it isnt connected properly or it is running to rich because the green light is steady lit... If anybody has this kit on a b16a2 or if anybody knows, which wire on the o 2 sensor should be connected, there is a green, white and two black wires, and i dunno if i have the correct wire connected, i had my volt meter but it is too confusing because two wires are getting voltage and the other doesnt. so can somebody please let me know which wire on the 0 2 sensor needs to be connected, please thanx