I am trying to install an O2 simulator for the secondary rear l/r O2 sensors. '99 CA-spec. The O2 sensor has 4 wires: 1 black, 1 gray and 2 whites. According to the simulator instructions, the black wire is signal, the gray wire is ground and the two white wires are either the heater signal or 12V power. Can somebody confirm that the black is signal and the gray is ground for our Maximas???

And can you guys help me figure out which of the two white wires is the 12V signal (and which is the heater signal)??? Please do not suggest turning on my car and using a volt meter - my car is completely taken apart for my header install. In looking at the O2 sensor plug below (this is the plug on the car-side), could you guys tell me which number is 12V and which is the heater signal? On my car 1 leads to the black wire, 2 to a white wire, 3 to a white wire and 4 to the gray wire. By referring to the numbers, could you please tell me what function each number performs? Thanks.

__
--------
| 1 2 |
| 3 4 |
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(Looking at the O2 sensor plug, car-side, terminal view)

 

IMO, those wires after the harness are a pain because they are slippery and difficult to tap/solder. Its just easier to tap into the wires before the harness.

Here's a write-up I did for the CALI spec 5th Gens so you can see what I'm talking about:

http://forums.maxima.org/showthread.php?t=468152

It was also much easier figuring out ground, power, and signal that way because the wires were all different colors.

 

Thanks Puppetmaster. I appreciate the link. For some reason, that thread did not come up in my search before I created the thread. After I posted, Ptatohed and I continued to look at the FSM and figured it out. We finally did, but after a few more hours. On one page, were it tells us how to test the O2 sensor etc etc, the pinout diagram is wrong and confused us forever! Then on just a plain wiring diagram on a different page, the wires made sense and showed the colors coming from the main wiring harness. We were then able to translate this to the O2 sensor wiring. We finally figured out which of the two white wires were power, the black wire is signal, the grey wire is ground, and the other white wire is the heater signal (leave untouched)

After all our research, and then looking at your link, it all confirms what we found out and makes perfect sense.

As far as where to tap, I'm hesitant to cut the main wiring harness. On the flip side, I'm cutting a perfectly good O2 sensor. I will definately take into considering what you said about the difficulty of taping the O2 sensor wires vs. the main harness wires. Thanks again.

 

So, which of the white wires is power and which one is heater signal? You said you've figured it out, but you've never bothered to expalin your find here. Can you elaborate? I'm about to do an O2 job for my GF's Maxima, conveniently, I'm also seeking an answer here.

-Peter-

 

Peter,

I was going to create an in-depth how to, with pics. But, since you're hungry for the information, here you go....

Looking at the wires directly behind (and connecting to) the O2 sensor, arrange the wires so black is at the 12 o'clock position, grey is at the 6 o'clock position, and the white wires are at 3 o'clock and 9 o'clock. The white wire at 9 o'clock is 12V power and the white wire at 3 o'clock is heater signal (leave untouched). Grey is ground, and black is signal. Hope that makes sense.

BTW, I decided to cut/splice/tap the O2 sensor itself. It wasn't too bad at all. I couldn't bring myself to cut the main wiring harness.

James

Note that I haven't started my car yet and seen if all is well. My car is still under the knife for the Cattman headers install. Also, what I described above is off the top of my head. I have it written down on a sketch in my FSM, which is at home. When I get home from work, I'll double check and report back here. Hopefully you can hold off your O2 project for tomorrow.

 

I just thought it was easier dealing with the wiring on the main harness that's all. Even if I am cutting into it, I'm just more confident I can work those than I am the O2 sensor wires. With the right tools, like a good soldering iron for one, the O2 sensor wires can be tackled, as you've already discovered. Glad you got things figured out.

 

Ok, just got home and checked my sketch. What I described above is correct. Good luck with your project Godfather.

 

For those installing the 02 simulator provided by Cattman, here's all you need to know. This was done on my 99 CA spec Maxima.

First, orient the O2 sensor so you're looking at the wires directly going into the back of the O2 sensor. Then, arrange the wires so black is at the 12 o'clock position, grey is at the 6 o'clock position, and the white wires are at 3 o'clock and 9 o'clock. The white wire at 9 o'clock is 12V power and the white wire at 3 o'clock is heater signal (leave untouched). Grey is ground, and black is signal.

Black wire coming out of the 02 sensor. Cut it and tape end off. Connect one of the yellow wires (doesn't matter which one) from the O2 simulator to the other end (The end going towards the main harness).

Grey wire coming out of the O2 sensor. Tap it with the black wire from the O2 simulator.

White wire coming out of the O2 sensor (3 o'clock position). This is the heater signal wire. LEAVE IT UNTOUCHED.

White wire coming out of the O2 sensor (9 o'clock position). Tap it with the red wire (12V power) from the O2 simulator.

You're done!

If simulating a second O2 sensor, all you need to hook up is the additional yellow wire from the O2 simulator to the black wire as I described above.

Last but not least, if you don't want to worry about which white wire to tap, you could simply run the red wire from the O2 simulator to any 12V switched power source. A switched power source is one that only has power when the car is running. Also, you could hook up the black wire from the O2 simulator to any ground, you don't have to tap the grey wire on the O2 sensor. I chose to tap all wires at the O2 sensor so all my connections are in one place, I don't have wires running all over the place, and I can easily electrical tape everything once I'm done and make it look OEM. No one will know the wiser.

 

i don't understand if you are looking at the end from the sensor or the plug??

also are there not any write ups for 95 range fed spec????

i don't think there is but one rear sensor on fed????

i am gonna sim both o2 and heated circuit, but i need to know what wire is what, and i too want to mount underneath car.

 

Is this only for 99's or does it apply to the 97 -98's?

 

This means the the wires going directly into the O2 sensor. I didn't mention anything about the plug that connects to the harness.

It's my understanding that your car and my car are the same. The only difference is I have an additional O2 sensor since I'm a CA spec. I simulated the right and left secondary rear bank O2 sensors, and did not touch the primary O2 sensors. So, with that said, all you need to worry about are the secondary O2 sensors. Hope that makes some sense.



See reply above.

 

It's my understanding that this applies to 95-99's. I'm no expert though on all the differences between the years pertaining to O2 sensors, so don't take my word for it. Hopefully a guru will chime in.

 

This only applies to cali spec 99's.

 

thanks for clearing that up.

 

so if i understand you correctly, the 12o'clock thing is with the sensor cut off, and looking at the end of the wires????

 

Nooooooooooooooooooooo!!!!! I don't know how else to explain it. You're looking directly at the back of the O2 sensor. Need a picture drawn up?

 

I have a 99 max fed spec and only the first two o2 sensorsare visible under the hood..the o2 sensor that is after the cat isn't visible under the hood..the wires run right up into the car from where it is located on the pipeing..how can I instal a dual o2 sensor on he fed 99 maxima?

 

also what colors for the fed spec are the power? ground and signal wires?

 

What exactly are you trying to do?

 

There's no power wire. There are 2 heater wires and 1 signal wire. The chemical reaction with the oxygen is what produces the voltages. It is grounded by shield wires wrapped around the heater wires.

 

so how can i install an o2 simulator

 

i looked under the car for the oxygen sensor because i was told this o2 sensor for the fed spec 99 max goes straight to the ecu. The wire colors are black grey and two whites. the o2 simulator i have is a dual simulator black ground wired red 12v wire and two white wires each for a sensor how can i install this o2 simulator???

 

Read post #8. In fact, read the whole thread again. I've spelled everything out. My yellow wires of the O2 simulator are your white wires on your O2 simulator. That is the only difference.

 

what happens if the wrong white wire (3 or 9 o clock) is pluged up to the white wire in my o2 simulator? will anything happen?

 

You're getting totally confused. Your O2 simulator white wires don't connect to the white wires of the O2 sensor. You connect one of your white O2 sim wires to the black wire on one of the secondary O2 sensors (per my directions above), and the other white O2 sim wire to another secondary O2 sensor if you so desire. IMO, you need to reread my directions above again and again and see how your wires translate to mine. It's really quit easy.

 

You don't need to.