Hi,
Yesterday the "service engine soon" light came out. I went to autozone to pull the code today and got P0138. The guy told me it is the bank 1 rear oxygen sensor circuit high voltage problem.
Which O2 sensor is that?
Where is it?

Should I replace that o2 sensor by myself or go to dealer?

 

read this TSB here, it should answer your questions. i had P0140 go off a couple months back and had the dealer cover it under extended warranty. they replaced both secondary o2 sensors and flashed the ecu.

 

Thanks for the information.
So this TSB is covered by the extend warranty and I don't have to pay?

 

replied to pm.

 

Thank for your information.
However I got different plan, Pre-owned-Plus. The o2 sensor may not be covered. I will check with nissan.

 

that would be the best thing to do. print out that tsb and take it in. tell them what kind of warranty you have and want to know if the work can be performed under there.

 

It might be covered under the emissions warranty. Read your warranty details before you take it to a dealer so you will be better informed.

 

Factroy Emmissions warranty only covers up to 50,000 Miles!

 

Here is a question:

Since the rear o2 sensors are causing so much trouble, and according to the service manual under normal operation condtions the engine does not use them to control anything, is there a way to bypass them?

In other words, does anyone make a device to plug into the harness and take the rear o2 sensor out of the picture (ie trick the ECU to thinking the rear sensor is there and working fine)????

 

try http://www.o2simulator.com or o2 simulator on ebay, they are around $25.

 

Very interesting.

Has anyone on this board used them???

 

Hey im new here...jus got my 2002 Maxima few weeks ago (about 45000 miles now) and the SES light came on so i took it back to the dealer and they said it was the O2 sensor so they scheduled me to come back to replace the sensors since im still under the dealer's warranty. My question is after reading the TSB should i just take it to the closest Nissan Dealer instead? Cause i saw there is an ECM upgrade that is included and im not sure if the dealer i got the car from can do that.

O.T. but since i see the MAF also goes on this car, how do i go about gettin my dealer or Nissan to fix the MAF if there is no perceivable problem with it yet?

 

I'd like to hear some more answers to this as I have the same problem... so BUMP!

 

I been recomending www.02simulator.com for a long time now. I have it on my cat-less-Maxima. Removing cats and installing headers or test pipes causes the Check Engine light to come on. You need to fool the computer to think that the Cats are there and working. So it intercepts the 5 volt refference voltage from the ECU to the 02 sensor, modifies it and sends it to the ECU. The 02 sensor signal wire is completly disconnected from the harness going to it- the simlator is pulsing on and off simulating a working 02 sensor and working cat. If the heater was to fail in the 02 sensor- they are heated 0xygen sensors in reality... then U need to repleace the sensor. If its some kinda voltage too high or low code, then get the 25 dollar simulator. For guys who have no cats on their header equipped Cali cars or even 3.5Ls I recomend getting the DUAL version they sell, it costs the same $$$. It provides signal to both 02 sensors behind the 2 cats and fools the computer I like mine.