masijdm

okay, so i got the car like this the primary sensor plug was done not right here is some pictures


1. Here is the wires that are connect its only 3 wires


2. Now there is the fourth wire coming from plug which i dont what color it connects to.


3. from the wiring harness there is this gray plug its also missing a wire



I've tried connecting that yellow with that Gray it didnt turn off the CEL ( I reseted ECU) it comes back on as "Primary Sensor" this wiring is really confusing. any help would be great.

Former User

Is this an EM1?

masijdm

yes its an EM1

masijdm

i am already starting to have faith in YOU LOLOOL

Former User

The primary O2 sensor has four wires that feed into four wires of the engine wire harness:

Sensor to Harness
White to White
Green to Grn/Blk
Black to Blk/Yel
Black to Blk/Wht

I hope this helps.

masijdm

i am missing one wire i dont know which one
i got
as you see in picture
white/blk
yellow/blk
green/blk

Former User

The white wire may have yellowed over time.

masijdm

what about this wire?

Former User

Quite possible.

joelmatt89

that weird because the white wire is the one that i though went to the ecu, but I am pretty sure one of the wires which i thought was the green one is a ground so maybe you don't have that, actually you may want to test that. If i were you i would test with the wires still connected. I would bet that you will have two with 12v or whatever the heating wires voltage should be. You also need the one that will have from .1-1 oscillating. If you don't have a ground it may just be grounding to the exhaust.Or maybe you only have one heater wire. I don't really know but it would really help if you tested the voltage on those wires after the car is warmed up. Do you have any cels, is it running good?

masijdm

so i just looked again i ripped out the the black cover there is no white lol its totally missing haha

esean93

Where can i get the wiring harness side plug for a o2 sensor?i might have to rig mine up like that if i cant find one.

Former User

The circuit diagram shows that the white wire supplies reference voltage to the O2 sensor whereas the Blk/Yel wire supplies battery voltage via fuse 15 to the heater unit of the sensor. The other two wires provide ground through the ECU and PCM.

masijdm

should i just buy the all harness? :? how much do tey go for

masijdm

i will look again for the white wire again i dont know which side too look for the white wire left or right? because it just goes

masijdm

cant find it :X

Former User

Maybe work backwards? The circuit diagram shows that the white wire comes from terminal 16 of the ECU C connector. Did you rule out that "yellow" wire?

masijdm

yes that yellow wire is with the plug, i just need the white wire that comes from ecu its just missing i saw it in ecu connecter but its gone half way i cant find it i will do it tomorrow

vtecgod

Hey does anyone have a suggestion i read this post, i'm having a o2 problem with my 99em1 low voltage code front sensor. I checked power and ground wire for it checked ok. And checked inside the car at harness plug too. With an multimeter with the key on position it read .39-.40vlts. I held the rpm at 3500 and then took my foot off the gas and the sensor started to read once it got back to idle it went straight 0. It's a brand new honda sensor any ideas? Will i be ok too drive too a shop without messing up the motor any?

vtecgod

Does anyone have any help with this I've checked fuses ground power and vlts. But the 02 is reading backwards. The car doesn't seemed to be running rich at all right now. If i disconnect the o2 and put the car in fail safe mode will it run ok and not dump fuel to make it to the shop?