O2 SENSOR. why run to the ecu? just get a multimeter to figure out wich of the 3 or 4 wires is signal, green is signal on some hondas. if you know how to do clean install with wires, it will look just fine to all the 2 inch high people walkin under your car inspecting the wiring. good luck, its an easy install. wire it in above the 02 harness, or into the top part of the harness. will save ya trouble if you have to yank the 02 sensor. 02 sensors are fairly usless, so have fun with the anoying lights.lol..