Hey guys,

Ive searched all over and read a ton of threads on the topics of o2 sensors but can seem to find what I’m looking for.

Somewhere in my cars past, some mechanic must’ve busted the o2 sensor plug on the engine harness side and decided to hardwire the o2 sensor to the harness.

So I went to replace the “bad” o2 sensor today (bank 1 sensor 1) and the new one is giving me the same codes. This leads me to believe that the old mechanic wired it wrong. Problem is, I can’t find the right colors to wire it correctly.

From the engine harness, I have a Thick Blue wire, a thin blue w/ yellow tracer, a white and a brown.

From what I understand, the Thick blue should be the data wire, the brown should be ground, and the white and the blue w/tracer should be the heater elements.

If anyone can confirm this it would be awesome!

Thanks for the help guys!

 

did a search for you...hope this thread helps...it’s an LS but might be the same
https://www.clublexus.com/forums/ls-...s-diagram.html

 

Thanks,

Ive read through that a few times and for some reason the SC is different. Instead of Black, Black, Brown, and Blue w/yellow The SC has white, brown, blue w/yellow and Blue (blue is shielding and there’s another skinny black wire inside the blue).

I changed the o2 sensor before realizing the clusterF the last guy created and now I’m worried that I’ve burned out the new o2 sensor. I fixed the wiring to what I think it should be but the codes are still showing a bad sensor... Did I also get the wiring wrong or did the new sensor just get burnt out from being wired Assbackwards... that’s the question.

Super frustrating.

Ive ordered another new o2 sensor and hopefully my new wiring is good and the new sensor will work.

I will say this, if any of you guys are near south FL and need a new o2 sensor, I’ll change yours out for free if you bring your car over and let me look at your wiring harness.

 

check out this thread...
https://www.clublexus.com/forums/sc4...g-diagram.html

 

Here is another thread with wire colors
https://www.clublexus.com/forums/sc4...ensor-1-a.html

 

Thanks BGW!

This appears to show what I said in the first post, correct me if I’m wrong.


The shielded wire (blue shielding w/black inside) is the data.
The Blue w/yellow tracer is heater.
The Brown is ground.
And white is the other heater.

Is that how you would read it Bgw?

 

Confirm this is what you are looking for and I will walk you through it. Paul

 

Wire color information as well as connector information. Paul

 

Thanks Paul,

please see last question below about damaged sensor.

I now have the car wired as:
Engine harness. > o2 Sensor.
Shielded > Blue wire
Brown > White
White > Black
Blue w/yellow > Black

Based on the diagrams, this should’ve solved the issue but I am still getting p0031.

I am thinking that due to incorrect wiring the first time, that the brand new o2 sensor may have been damaged.
Thoughts?

 

see if these additional pics clear it up a bit.

 

Im not sure what you are doing. The O2 sensor is wired directly to the Engine Control Module. Can you take a picture for us?

Paul

 

Yes some mechanic before me broke off the plug and hard wired the upstream o2 sensor directly to the engine harness.

Once I noticed his screw up, I fixed it.

Im just trying to confirm that I got it correct because the new o2 sensor is still throwing codes.

I know I got OXL1 and HTL correct.
And from what I can tell on the wiring diagrams, BR is GROUND and W is the return for HTL.
- This is how I have it wired now.


Is it possible it’s still throwing codes because the new sensor was damaged from being installed with bad wiring the first time?

 

it could be damaged...let me look in the manual for a test procedure.
i have seen a few videos etc online to test a four wire O2 sensor...
my service manual collection ;-)

 

White ties into point A in the bottom right. It is not a return. It ties into multiple emmision system components including the MAF. Paul