# 05 VQ Altima p1273 help please!



## K11altima05 (Jun 30, 2016)

05 Altima vq35de with 146,000 , I have had a check engine light on since January for a p1273 b1s1 lean shift, I have searched high and low through multiple forums for an answer and have tried multiple tests to no avail on what it could be. I started by replacing the b1s1 with an oem ngk af sensor and did the relearn procedure only to have the code come back, the shop then recommended I replace my y pipe because of a small exhaust leak so I bolted on a racing line y pipe only to have the code come back. So they then hooked up their live scanner and found that the bank 1 sensor 2 was not reading correctly even though there was no code for it they said that if its not reading correctly it will set off the code for the 1st sensor? So I replaced b1s2 also with an ngk oem sensor and the code is STILL coming back. My father in law tested the wiring on b1s1 at idle and fluctuated around 1.5v like it should and according to the shop b1s2 was not fluctuating and was staying around .24 volts. So I am at a complete loss and have no idea where to look next or what the issue could be every forum I've been on, anyone who has had the same issue never really posts if they ever fixed it and any tsb I have looked at is for the 4cyl qr motor so any help at all would be GREATLY appreciated!!!


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## K11altima05 (Jun 30, 2016)

Can anyone help me out?


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## smj999smj (Jan 1, 2006)

When you get a P1273 code and replace the air fuel sensor, you have to use a scan tool to erase the stored codes AND then the self-learning control or the code could come back. I believe there was a TSB on the subject.


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## K11altima05 (Jun 30, 2016)

I read the tsb but it stated it was for the qr 4cyl motor only... And when you you say scan tool are you referring to an autozone scanner or a Nissan dedicated scanner? Because I have a matco scanner to clear the codes


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## smj999smj (Jan 1, 2006)

A Nissan Consult II or III would work or any generic scan tool that has similar capabilities. That would be a "no" on the Autozone and a "maybe" on the Matco scan tool, as I don't know what the capabilities are of that tool. IIRC, the self-learning control is under the "engine" category and then under "work support."


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## K11altima05 (Jun 30, 2016)

The matco scanner I have is just a basic scanner to see the codes and erase them that's it, so should I bring it to the dealer and have them use their Nissan scanner to reset everything?


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## K11altima05 (Jun 30, 2016)

Anyone else have any recommendations? Still having the same issue


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## 05VqAltima (Jul 24, 2016)

Do you have any cats on your car?


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## K11altima05 (Jun 30, 2016)

Yes cats are still on the car it's all stock


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