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Chris(aka-Moose)
Chris(aka-Moose), Nissan Technician
Category: Nissan
Satisfied Customers: 46449
Experience:  16 years of experience
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My Sentra Nissan 2.0L does nor complete O2 sensor monitor,

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My Sentra Nissan 2.0L does nor complete O2 sensor monitor, but it doesn´t have any trouble codes and machine works fine
JA: Have you located all of the vehicle's oxygen sensors? Are the wires leading to and from each intact and in good shape?
Customer: Yes, mexican version only has two sensors, one after and the other before catalyst. All wires looks good
JA: What year is your Sentra?
Customer: 2011
JA: Are you fixing your Sentra yourself? What have you tried so far?
Customer: I scanned with a elm adapter and my smartphone, I checked all wires visually
JA: Anything else you want the mechanic to know before I connect you?
Customer: I took to the dealer and they recomend wash the acceleration chamber, change spark plugs and clean fuel injectors, but they are not sure all that things assure my car complete that monitor.

Welcome, I'm Chris (aka Moose), my normal schedule online is around lunch and after dinner till early morning.

With no codes stored, the O2 sensors showing to be reading correct, and the drive cycle completed. The computer is to blame for this monitor not completing.

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Thanks for using Just Answer, Chris

Customer: replied 3 months ago.
Chris, sorry, I could not answer until now.How can I assure computer is the problem?When I began to scan my car and noticed, it could not complete O2 monitor, I looked around and I could scan two more Sentras.
First was 2010 year model and it made exactly the same with mine, all monitors are completed except O2.
Later I scanned 2008 year model and repeated the same problem, from 6 monitors it showed, all were completed, except O2 sensor.
I began to think if the program in computer had a bug, but here in my country I have not founded anybody who guide me to correct the problem.
Last year, began to use OBD scan in order to verify gas emmisions in México, before that, they used a program to measure gas emmisions and my car never had any problem to pass verification.
Actually my car runs smooth and without trouble codes reported.
When I went to dealer, they recommend me, to wash aceleration chamber, change spark plugs and clean fuel injectors, but they did not assure these could fix the problem.
I did it, and my car does not complete O2 monitor. After this I tried to follow Nissan driving procedures to make computer complete all monitors and it did not. All are completed except O2
How can I found where or which device is failing?
I am looking on Sentra workshop manual and I could not found anything clears which device is failing
Thanks in advance for your help
Sorry for my english

You mentioned there are no codes. If a monitor has not completed then P1000 would be stored.

Customer: replied 3 months ago.
Chris, good day:
Yesterday I scanned my car again
First time with a Pocketscan by Bosch, it showed 7 monitors reported: 1 incomplete ( O2 sensor) and 6 completed, Misfire, Fuel, Comp, Catalyst, O2 heater, EGR. MIL off and zero DTC.
Later I made the same with an ELM adapter and OBD auto doctor Pro on my smartphone and it showed:
DTC confirmed 0, pending 0 permanent 0
Sensors:
Bank 1 sensor 1 wide range O2 S average = 2.200
Bank 1 sensor 1 wide range O2 S equivalence ratio lambda = 0.994
Short term fuel trim bank 1 = - 4.2% average
Long term fuel trim bank 1 = 7 % average
Control module voltage = 14.13 V average
ECU description:
OBD = EOBD EuroOBD
Control module 0X7E8
Calibration id = 1ZJ82C
Calibration verification = 0C0C6C7DI hope it can help to clear what is happening with my car
Thanks in advance

If there is not a P1000 code stored then the computer thinks all monitors are complete. Is there a running issue that is directing you to try and address the O2 monitor not completed?

Customer: replied 3 months ago.
Both scanners show O2 monitor incomplete.
Since last year, government was using OBD protocol to check car status and the five mandatory monitors completed are:
catalyst, O2 sensor, misfire, fuel system and CCM.
So, if my car does not complete O2 sensor, I can´t get my "0" sticker and I can´t use it daily.

All symptoms point to replacing the vehicles computer

Customer: replied 3 months ago.
Could I upgrade or renew the program on my car computer?
I think there is a problem with software not hardware

A dealership can reprogram the computer to the most recent software release.

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