The rear O2 sensor (downstream of the cat) failed. I had both codes 0512 and then 0912. This lights up the SES warning lamp, but the ECM does not use any other signal from the rear O2 sensor as input to manage the fuel and ignition system in a closed loop operation. The only purpose of the rear O2 sensor is to monitor the function of the catalyst. So I didn't care much about having a functionning rear O2 sensor. I wanted a creative solution to turn off the SES lamp. A search on ebay resulted on a "O2 sensor simulator".

I ordered one unit and installed it. My installation also included 2 additionnal 25 ohms resistors rated for 15 Watt load to simulate the O2 heater function. The ECM also monitors the heater function of the O2 sensor. So I had to take care of that error code as well to have the ECM turn off the SES lamp. I tapped in the 2 resistors in series in place of the heater wires. As an alternate to resistors I think a simple 12V 3Watt automotive bulb ( No 194) could have simulated the heater function of the O2 sensor.

The whole installation went smooth, and the ECM switched off the SES lamp. I recommend very much the DualO2Sim. It costs much less than a genuine rear O2 sensor. Please remember this simulator works only for the rear (post catalyst) O2 sensor.

Wanted to share my experience with all.

 

How much did this cost you? Could you possibly do a step by step writeup?

-Nick

 

The simulator is offered at $30. A genuine O2 sensor costs at least $60. I can make a write up. I will post it later.

 

http://oxygensensors.com/index.php
$44.95 - Free shipping
And it actually works- prob. an easier install to
1 rule:
If its there it prob. does something.

 

I agree with you. The economics get greater for those who have to replace 2 rear O2 sensors.

 

This is my write-up:
Installation the O2 sensor simulator

The rear O2 sensor has 4 wires (on my 1998 Maxima)

1- Black: low Voltage (0.1 to 0.9 V) very low amperage signal generated by the sensor itself
2- Grey : car chassis ground
3- White: the O2 sensor heater 12V positive feed ( switched on with ignition key)
4- White: the O2 sensor heater ground (not connected with wire 2- ground, not the same. This wire runs to fuse number 31 (1999 model year ) or 34 ( 1995-1998 model year) ).

To install the O2 sensor simulator:

Cut all 4 wires of the O2 sensor. Cut the wires close to the bad O2 sensor. That will give you some good wire length after the connector located under the driver’s seat. (On my 1998 Maxima the connector is located under the driver’s seat. This is where the O2 sensor wires emerges from under the car through a rubber grummet). Leave the bad O2 sensor in the exhaust pipe.

The sensor simulator also has 4 wires:

a- red : a 12V input to feed the simulator
b- black: ground
c- and d- : 2 purple wires: O2 simulated signal ( one for each actual O2 sensor if the car is equipped with rear O2 sensors).

Use a voltmeter to identify which of white wires above (3- or 4- ) is the +12V feed. The voltmeter will show +12V signal with wire 3-. Connect this wire with wire a-.

Connect wire 1- with wire c- or d- . (My car only had one O2 sensor ). Leave the other purple wire unconnected if you have only one rear O2 sensor.

That will take care of ECM code 0512 Downstream oxygen sensor high voltage fault.

In my case I also had to simulate a functionning O2 sensor heater. I used 2 x 25 ohms resistors (rated for 20 watt each) and connected in series them between wires 3 and 4. Polarity is not important for these. Under 12 V these should dissipate 1.5 Watt each, with 0.24 amps running through them. Be careful where you locate these because they get hot. Not burning hot, but hot. I tied these down under the driver’s seat. I estimated this area had enough open air to dissipate the heat. That took care of ECM code 0902 (Downstream oxygen sensor heater or circuilt fault).

I have not tried but I think a simple 3Watt automotive bulb (No. 194 for example) connected between wires 3 and 4 will do the job of fooling the error code 0902.

I found the O2 sensor simulator in ebay.com Look for “O2 sensor simulator”
The supplier, Baker electronics, includes a detailed electrical schematics fot installation.
This simulator will not detect a malfunctionning catalyst. Therefore check with your local regulations for compliance of such an installation on your car.

 

Thought i'd revive an old thread with some pics to help others with an o2 sim install


I followed twiggy144's wire codes and o2simulator.com's installations codes.

I used a sharp knife to slice through the plastic on the wires (DONT CUT). The o2 sensor wires are hard to work with, so i sliced the harness' wire.I also left the o2 sensor in to simulate the heater signal but i cut the Sensor's signal wire (black)..

so following twiggy's instructions,

1/ find the signal from the o2 sensor (my case, black)
2/ find ground (grey)
3/ find 12v. (white, tested with a test light by toggling ignition)
4/ connect o2 sim to them, then cut the signal from the o2 sensor.

If u need to get rid of the sim..just pull wires out and tape up the slice. (no cuts involved..except the cut from the o2 sensor signal wire..my sensor was failing so i didnt care.

Any questions lemme know..


P.S.
97 Maxima GXE.

 

more pics

for a video of it working:

http://www.youtube.com/watch?v=bhA-Ucw7cQM

 

Could we use an old Up-stream o2 sensor to simulate the heater signal? I believe those also have 2 white wires.

 

yes, but the harness wont be plug and play anymore...you can also use a resistor to simulate the heater signal if u decide to get rid of the sensor all together.

 

I just noticed its 40 bucks for a o2 sim. I think i rather just install a real o2 sensor and have everything to normal. O2 sensors are around 45$

anyways, good work.

 

i'm getting a cattman ypipe regular sim will pop a red light lol

 

huh?

 

lol?

the cattman ypipes and other aftermarket (off road) doesnt have the Catalytic converter(s) so the o2 sim will report a code ..i think PO1441? thats why we use o2 sims. Hit the readme's for a nice write up

 

There i fixed it for you.

But i will say, an aftermarket Y (without pre-cats) will not pop a CEL, removing the actual Cat will though.

 

ah ok. I have a warpspeed so I was unaware.

 

Rear O2 has no significance in engine tuning, therefore any generic rear O2 will turn light off.

 

when my ses for my rear o2 came on, i used a anti fouler. worked great no more ses.

 

[quote=khemraj1999;7637899]Thought i'd revive an old thread with some pics to help others with an o2 sim install


HEY BUDDY WHERE I GET THIS SIMULATOR IN CIUDAD JUAREZ CHIHUAHUA?
my 97 maxima had a code of this sensor the service engine soon is not turned on but fails for example
sometimes this not iddling and do abruptly thath makes me crazy and sometimes the car shutdown in a stop light and doesn;t want turn on but i got to depress all the acelerator to can start it doesn;t expulse smoke but smell to smoke is expensive or cheap that simulator?
sorry but i dont speak english i'm mexican ... i wait you answer
thank you
oh i forget it i need the simulator because my o2 sensor does not get out is burned or someting
is very hard pff
is a 5 speed maxima 3.0

 

compa, tu problema no es el o2 sensor. Es otra cosa... Si le estas dando gas para que prenda el carro, checka los sensores del crank, cam, y la tierra a la transmission. El maxima no necesita el sensor de atras para que corra bien.

 

genial que alguien me contesto en espanol pues mira te explicare en si el problema entero

en la manana lo prendo y todo muy bien hay veces que solo dejo que llegue a la temperatura normal y como que las revoluciones bajan demasiado aveces es tanto lo que bajan que hacen que tiemble el motor y pues se apague y luego cuando le doy start de nuevo le tengo que acelerar para que acelere y luego acelera de jalon y pues tambien has de cuenta que voy en 3era velocidad y bien suave pero derrepente empieza a como que desacelerarse y se tironea y si en ese momento le quitas la velocidad y se queda neutral se apaga
y cuando lo dejas asi prendido un rato derrepente se apaga y como dije huele a humo pero no hecha porque lo lleve al ecologico y lo paso muy bien lo que se me hizo raro fue que lo lleve a checar por la computadora y me salio el sensor que esta por el catalizador y el sensor de velocidad que ese si falla ese si lo he notado porque aveces no marca el velocimetro pero nadamas emm y el sensor lo iba a limpiar pero resulta que esta pegado o soldado el caso es que no sale y lo lleve con un disque mecanico y me dejo peor porque el barrio la rosca me dijeron que mi unica forma de sacarlo era destemplandolo pero bueno la verdad ni se que es eso pero en fin emm gracias por tu respuesta me podrias decir cual es el sensor del crak que menciones y el cam y eso que dices? donde see encuentra esque no tengo mucho con el y no lo conozco a plenitud :P