Need help on telling what wires are what on a o2 sensor quickly!!!

Ttop34 · 07-08-2002, 09:38 PM

I'm guessing this is where I can put this since there really wasn't a good place to. If it should be somewhere else to get better responce then somebody please move it.

The instructions I have are for a Mustang so the colors of my wires aren't quite the same. On the mustang there are two white wires for 12V Heater and Heater Ground, a Grey wire for Output Signal and a Black Wire for 450 millivolts reference signal sent from the computer.
In my o2 sensor I have two brown wires which I'm guessing to be the heater wires, a purple wire and a lavender wire(light purple).

I would guess the darker colored wire to be what the black one is on the Ford but that's just a guess. Does anybody know what these are for sure?

Also, I'm assuming that our o2 sensors work the same as Ford ones right?

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2000 Red Camaro w/t tops, Y87 and 5spd
Mods: FTRA, K&N, Whisper Lid, 180* thermostat, Jet Chip Stage II, custom high flow cat, 3" S pipe, American Thunder Catback #17133, removed spare and jack
60': 2.244(best: 2.234)
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1/4: 15.362 @ 90.04mph(best: 90.89mph)
(@Idalou, Tx where a stock LS1 can only pull a low 14)
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Racing · 07-09-2002, 12:37 AM

You sure about the schematics?
Colour code you give for the OEM sensor is the same as for any and all Bosch,but..
White=+ and - for heater
Black is sig
Grey is sig ground.

Ttop34 · 07-09-2002, 10:12 AM

Well I don't have a Bosch sensor, I have whatever they put on there stock and last I checked, I wasn't color blind.
Is there anyway you can tell me which wires plug into where on the plug? Maybe with looking at the plug with the clip pointing up, what are the colors of the wires?

Ttop34 · 07-09-2002, 12:53 PM

I just checked at Autozone and the replacement o2 sensor has the same colored wires as mine does. The guy even said they were the first he'd seen that weren't white, grey and black. If somebody can look at their o2 sensor and see if they have two white,a grey and a black wire then please post and tell me what the positions are.

Soma07 · 07-09-2002, 01:31 PM

If its a stock GM sensor the wires should be labeled A,B,C,D on the black plug.

A = Low res signal (??? never found out what its for)

B = High res signal (to PCM)

C = Ground for heater

D = +12v for heater

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Jason
93 TA, M6

Injuneer · 07-09-2002, 02:26 PM

I think what they call "low res" is in fact the ground. The PCM applies 450mV to the sensor, so what the PCM sees back is the resultant of the 450mV from the PCM and the plus or minus mV from the sensor. When the sensor is cold, it produces no voltage, so the PCM shows 450mV on cold start, its own bias voltage.

In the 93's, with the one-wire unheated sensor, that part of the circuit relied on the sensor being grounded to the exhaust. I guess having the ground hard wired is a little more reliable, when dealing with millivolts.

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Fred
94 Formula A3: 381/TH400/N2O

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Ttop34 · 07-09-2002, 02:44 PM

So your saying that the B/purple is the 450mV from the computer and the A/lavender/tan is the signal returning to the computer?

That's what I would have guessed just going from the shades of the wires and how it compares to the Ford wires.

Also, given these instructions http://www.zx2racing.com/mods/mods_mil.htm, do you think I should go with the 1/2 or 1/4 watt resistor?

[This message has been edited by Ttop34 (edited July 09, 2002).]

Soma07 · 07-10-2002, 01:56 AM

Quote:

<font face="Verdana, Arial" size="2">Originally posted by Injuneer 94FormM6:
I think what they call "low res" is in fact the ground. The PCM applies 450mV to the sensor, so what the PCM sees back is the resultant of the 450mV from the PCM and the plus or minus mV from the sensor. When the sensor is cold, it produces no voltage, so the PCM shows 450mV on cold start, its own bias voltage.

In the 93's, with the one-wire unheated sensor, that part of the circuit relied on the sensor being grounded to the exhaust. I guess having the ground hard wired is a little more reliable, when dealing with millivolts.

</font>

Sounds good to me, funny thing is on my 93 (w/heated 4 wire sensors) I dont have that wire grounded and the sensors still work fine. It shows 450mv on a cold start just like it should.

Maybe the wire us just acts like an extra ground in case the sensor itself isnt grounded well?

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Jason
93 TA, M6