rdlsz24

I just bought a universal NGK oxygen sensor from sparkplugs.com. I had to go with the universal since my truck has an engine swap and there is no plug; the wires are just soldered together. Here are my 4 wires going to the existing o2 sensor:



The 4 wires are:
white w/ red stripe
pink w/ green stripe
brown
black

Luckily, they match up (at least it looks that way to me) with what I have boxed in red in this wiring diagram:

http://www.freewebs.com/toyotastuff/PDF/22RE_Wiring.pdf

I can't tell which wires are for what on that diagram. So what I need to know is which two wires are for the heater, which is the ground, and which is the input?

Thanks,
Rob

rdlsz24

Newer than '86 has 4-wire o2 sensor. I fixed the wiring diagram link so it should be public now. I see my wires on the diagram; I'm just not sure which is which since it isn't labeled clearly. I just need someone who is better at reading wiring diagram jargon than me

Rob

colsoncj

funny, my 87 has a 1 wire o2. parent's 94 had a 4 wire. wonder why yours is a 4 wire....

id say the diagram looks good, and if it matches what you got in your rig, go with it. it appears the heater wires are the brown and pink/green, with the brown being the ground for the heater; the input is black and the ground is white/red.

rdlsz24

I could have swore I read on here somewhere that '86 and newer had 4 wires. Maybe it was '88 and newer? Mine does have a 22RE swapped into it in place of the factory 3.0; maybe it was from a newer truck. Either way, you gave me the info I was looking for. Thanks

Rob

ewong

https://www.yotatech.com/forums/f116...-where-133590/

rdlsz24

Thanks ewong. I took a look at the AutoZone wiring diagram and it has the same wire colors as the first diagram I posted above, but it shows the grounds for the heat and the main ground switched (here boxed in red)

http://img.photobucket.com/albums/v6...ck/wiring2.gif

So the FSM diagram shows:
input - black
ground - white/red
heater wires - brown (ground) & pink/green

The AutoZone diagram shows:
input - black
ground - brown
heater wires - white/red (ground) & pink/green

Which do I believe? The AutoZone one seems more believable, but I would tend to believe the FSM diagram would be right. Anybody actually wired one of these up? I think I may have an '89+ ECU by the way.

Thanks,
Rob

rdlsz24

Anybody?

Rob

nate V

to the best of my knowlage that the brown wires in toyotas are typicaly ground. I will look at my toyota diagrams later today.

nate V

I as well have been having some issues with the 02 circuit.

hijack: do you know why the black wire has a shielded braiding on it???
I look mine apart a while back and the wires are not spliced properly just kinda stuck together. anyone else have this on their truck??? It seems to me that if it is shielded then it must be the input wire to the ecu.

rdlsz24

That's what I'm thinking, but is it the main ground or the ground for the heater?

Rob

rdlsz24

Right but here is what I am installing:



I need to know which 2 wires go to the heater (white) wires on my sensor. I don't want to run the main ground to the ground for the heater, right? Or is a ground a ground?

Rob

ewong

I ran into a similar issue when wiring a "universal" 02 sensor into my VW.

The issue is the heater - as the two wires are "white" on the universal sensor????

Its a RESISTIVE heater - so it does NOT matter if you swap the two white wires.. it will work either way.

Is how you "read" the FSM thats causing confusion

BOTH the BROWN and the white/red end up a ground.
The HEATER is "grounded" via the ECU - hence the "cufusion" when reading the FSM.
(Thus a Ground is not always a ground)

There should be FOUR wires in the harness to the O2 sensor - as you noted in your first post

connect as follows
Harness BLACK to Universal Sensor BLACK
Harness BROWN to Universal Sensor GREY
Harness WHITE/RED to Universal Sensor WHITE
Harness PINK/GREEN to Universal Sensor WHITE

I HOPE thats clear enough

rdlsz24

Thanks ewong

nate V

well there you have it thanks ewong
hijack again. does the ecu need to be bolted to the body in more than one place for it to correctly ground.????
i know silly question but right now i only have it bolted once just curious.

Admiral Goose

Thanks ewong! I just completed a rebuild and previous owner cut the O2 wires. In testing the wires, the white-red had 12+, pink-green had 3.5 volts and brown was grounded. It took some time to find a post with this key info.

The pics below show the Bosch universal connector with the wires hooked up the incorrect way based off my voltage tests. I had the brown and pink-green crossed as all the instructions from multiple websites said the polarity did not matter for the heater. Since brown came up as a ground I assumed it would need to go to a heater wire (white) with a positive which was white-red. Didn't even think for a minute the ECU was advanced enough to have a switched ground back in '91. Still learning each day...