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Mike S.
Mike S., ASE Certified Technician
Category: Nissan
Satisfied Customers: 6703
Experience:  ASE Certified since 1985
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I have an issue I needed some help with. I have a 2004

Customer Question

Hi Mike.. I have an issue I needed some help with. I have a 2004 Infiniti G35X.
Submitted: 1 month ago.
Category: Nissan
Customer: replied 1 month ago.
Good Day,
I have a 2004 Infiniti G35X V6. Back in July I got a check engine light with codes, most of the codes were related to the fuel/ air mixture/ratio or lean condition. The codes were P1148, P1031, P1148, P1276, P1278, P1279. So I figured I would change all 4 O2 sensors since I have no way of checking them. So I ordered 2ea of the BOSCH 15667 O2 SENSOR, OE TYPE FILLAMENT, 1ea of the BOSCH 15522 O2 SENSOR, OE TYPE FILLAMENT; and 1ea of the BOSCH 15523 O2 SENSOR, OE TYPE FILLAMENT. I used Bosch and not OEM cause I was told that Bosch actually manufacture's the OEM sensors for Nissan/Infiniti cars. After I installed them, I got a new code which I don't understand and this one as well is related to the Fuel Air Ratio, Code P1273. I thought maybe the O2 sensors would have to get used to the system so I let in sit for about a month using the car regularly. In any case we are almost 2 months later. I've reset the code many times and I still get the code never on the highway but during idle or in traffic. Don't know what else to do at the moment. Would like some help..
Customer: replied 1 month ago.
The code P1273 is the only code I'm getting at the moment.
Expert:  Mike S. replied 1 month ago.

I am sure you know by now that P1273 code refers to a A/F sensor. About all I can do is provide you with a troubleshooting procedure, cause honestly I have never diagnosed a code P1273 on this particular vehicle before. Here is the entire article, that includes some troubleshooting.

Just some quick note though, from reading over it, check for intake leaks, check the fuel pressure, check the grounds, re-tighten that sensor, check the voltage to it, check the sensor for an open/ short.

Customer: replied 1 month ago.
Hi Mike, but which sensor would I need to check as I replaced all 4?
Expert:  Mike S. replied 1 month ago.

A/F sensor. I thought you said you replaced 4 O2 sensors.

Expert:  Mike S. replied 1 month ago.

Unless Nissan is calling o2 sensors A/F sensors. I think maybe they are. I am not familiar with that term though.

Expert:  Mike S. replied 1 month ago.

I did find P1273 refers to bank 1 sensor 2 lean.

Expert:  Mike S. replied 1 month ago.


"Clear the engine ECU Self-Learning.

IMPORTANT: If Self-Learning Is Not Cleared:

  • The DTC may be stored again; even if no malfunction exists.
  • This could result in the customer returning with the same incident ("come-back" repair)."
Expert:  Mike S. replied 1 month ago.

Here is that entire procedure for self-clearing.

Customer: replied 1 month ago.
Hi Mike, Can I Clear the ECU without any tooling. Or do I require a special tool or OEM scanner/analyser to do it.
Expert:  Mike S. replied 1 month ago.

I believe you will need the CONSULT-II tool. Normally anything after 1996 you need a tool, before then you could just disconnect the battery or remove the fuse for the ecm.

I don't actually own a CONSULT-II tool, so I wouldn't know anything about how to use one. if they are too expensive you may want to just go to your closest Nissan dealer and have them do it.

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