# O2 Simulator Installation Information



## Puppetmaster (Mar 28, 2005)

*USE THIS WRITE-UP AT YOUR OWN RISK, I AM NOT RESPONSIBLE FOR ANY DEATH/INJURY/DAMAGE SUSTAINED BY YOUR USING THIS*

O2 Simulator Installation (this is really just a rehash of BlackbirdVQ's write-up but for the fact that I included pictures that I took tonight)

This should work on all Cali spec Maximas. When dealing with codes P0420 and P0430, whether its voluntary removal of or just bad pre-cats, the O2 sim helps keep your SES/CEL/MIL light off and typically also prevents the ECU from storing any related codes. Rear 02 sensors only monitor if the cats work and do not affect the long or short trim fuel so basically, they do not affect drivability or the air/fuel ratio. Since the ECU is monitoring catalyst efficiency using the rear O2 sensors and the O2 sim simulates the proper voltage for the ECU to think that the cats are working. For more info, see www.o2sim.com.

The wires tapped into are the wires before the connectors for the rear/downstream/secondary O2 sensors. The dark blue connector is for the Bank 1 (rear bank) downstream O2 sensor. The green connector is for the Bank 2 (front bank) downstream O2 sensor. Cut back the black wrap before each connector and you should see 4 wires: 

Black: Ground
White: Signal
Red/Yellow: Power
Red/Blue: Heater











If you are going to simulate BOTH secondary O2 sensors, be sure to have bought a dual output sim with one black wire (ground), one red wire (power), and two white wires (signal).










_The installation for a single output sim is the same, except you just tap into the signal of the sensor you want to simulate instead of both. _


On ONE O2 sensor harness:

Using a wire stripper, strip about half an inch to expose the copper wires under the ground and power wires. 

Tap the black wire from the O2 sim to the black (ground) wire. 

Tap the red wire from the O2 sim to the red/yellow (power) wire. 










Cut the white signal wire and connect one of the white wires from the O2 sim to the end that is going back to the ECU. 


On the other O2 sensor harness: 

Cut the white signal wire and connect the second white wire from the O2 sim to the end that is going back to the ECU. 











Heater wires: 

Leave em intact and both secondaries plugged into their respective connectors, the ECU still needs to read these or it will throw a code for heater malfunction or something.


You can now either solder the joints and wrap them up in heatshrink or electrical tape, or you can clear the codes and start the car to see if the sim is doing its job before soldering. The yellow LED on the sim should be blinking when the car is on/running. 












Other links:

BlackbirdVQ's write-up: http://forums.maxima.org/showthread.php?t=361017

If you want to completely remove and simulate your secondary O2 sensors, even the heater wires: http://forums.maxima.org/showthread.php?t=435399


All comments, criticism, or questions are welcome....


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## mjn030 (Jul 21, 2009)

*Question about this o2 simulator and the OBD II readings*

First let me say that this looks awesome ! I am wondering though if after installing the o2 simulator, will the OBD II readings actually give you a valid reading to pass inspection ? Or will it continue to say something like N/A or unsupported, similar to that when you reset the codes ?

Thanks 
-M


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