wondering about oxygen sensor wiring

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URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=104815
Printed Date: May 09, 2025 at 8:22 AM

Topic: wondering about oxygen sensor wiring

Posted By: Fosgate3
Subject: wondering about oxygen sensor wiring
Date Posted: May 18, 2008 at 7:07 AM

I have a 2007 Saturn Ion3, 2.2L. I was wondering what the four wires on the o2 sensor are for. There is a Pink/Black that reads 12v, a Tan(or Light Brown)/White that reads ground, a PURPLE / White & BLACK/ White that fluctuate in voltage, neither of which go over 2.5volts. Which one is the actual signal wire from the sensor to the ECU?

Replies:

Posted By: Velocity Motors
Date Posted: May 18, 2008 at 8:06 AM

Heater circuit Ground Wire

Heater circuit Positive Wire

Sensor circuit Ground wire

Sensor circuit Positive reading wire

These are the wires descriptions of common 4 wire o2 sensors. Hope this will help you in determining what the wires are for with the help of your DMM.

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Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA

Posted By: Fosgate3
Date Posted: May 18, 2008 at 8:57 PM

Thanks VM. Given the wiring colors I listed, I would at least guess that...

Pink/Black = Heater circuit positive wire (since it read 12v positive with the engine running)

Tan/White = Heater circuit negative wire (since it read ground with the engine running)

The question remains is which would be the sensor ground and sensor reading wire. Shouldnt the sensor circuit ground wire read as a "ground"? I will double check it to see if it did or not... it will be a toss up between the BLACK/ white and PURPLE / white as to which is ground and which is signal.

Posted By: chriswallace187
Date Posted: May 19, 2008 at 10:20 PM

Fosgate3, you might like a Chilton or Haynes guide, or AllDataDIY - the last is about $15/year for a one vehicle subscription, and you get access to complete wiring diagrams for the vehicle, TSBs, mechanical stuff, etc.

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C Renner's Auto Electronix
My service is cheap, quick, and good - pick any two

Posted By: reax222
Date Posted: August 24, 2008 at 4:20 AM

What are you trying to accomplish?

The wire that varies from 1-5v is your signal wire.

Posted By: tilar
Date Posted: September 28, 2008 at 8:38 AM

I'd guess he was trying to wire in an EFIE device.

Wiring schematics for that might be something else that could be added to the web site.