B18CivicEH2

i was reading on wiring O2 sensor on CX hatches and i know you have to add 3 wires if you use the CX harness and CX ECU....i have a B18B with the LS P72 ECU and the engine harness i have has the VTEC plugs so i know its not the CX harness...i noticed that the O2 plug on the harness allready has 4 wires but i was wondering if i had to add 3 wires to the harness that goes from the ECU to the Engine harness???