Infiniti M45 P2A00 error easy to replace?

[bdavis007]

My 2006 M45 is throwing P2A00....How easy is it to replace the upstream left sensor? Is this something I can replace from the hood? I have searched and there seems to be alot of info on the M35, but not the M45.

Thanks!

[Ilya]

Is the upstream the one right after the engine? If so, and if it's anything like the M35, I didn't change them. I literally did not know how to get a tool in there (it's VERY tight) to get the sensor out. I only changed the bottom two which were wide open and easy to access.

[Costee]

A nasty code that. Usually, the sensor is not even the culprit but a tiny leak somewhere thereabout.

[bdavis007]

It is upstream left/driver side. What is usually the culprit? Should I skip replacing the sensor and have a dealer look at it?

Thanks guys!

[EdBwoy]

Depending on how much time, ability you have to tinker with the car + it's driveability etc, you could try to follow the troubleshooting guide on the FSM. Starts around pg. 1387 on the EC section.
In summary, the FSM says it could be any of these:
-A/F sensor 1
-A/F sensor 1 heater
-Fuel pressure
-Fuel injector
-Intake air leaks

To answer your original question, yes. You can remove the sensor from the hood. Need an o2 sensor socket with a pretty long extension. I had my car jacked up when I did my passenger side so I broke it loose from the top and finished the job from the bottom. Easier to work on it down there after it's loose but not too many tools can fit well from underneath.

When I had to replace mine, it was a pretty clear failure with 2 codes that I can't retrieve at the moment. I feel that a sensor replacement is not warranted at this point yet.