I checked the codes on the ECU today, and it came up with 0901, which is upstream O2 sensor heater fault (right bank). I dont quite understand what the heater fault part of it is. Can anyone shed some light on this one? Will changing the O2 sensor make it clear away, because it comes back on after a few minuets of driving.

 

Change your O2 sensor. O2 sensor codes pop up all the time on Maximas (Nissans, for that matter) and I've never found a wiring problem related to it. The O2 sensors must be getting made by some cheapo company somewhere, because the new Air/Fuel sensors are the same way.

 

I have been wanting to change them for a while, guess now is a good time to finally do it.

 

What did you end up doing here?

 

One of the wires on the O2 sensor is cut, I havent fixed it yet, but thats all it is.

 

Any change in gas mileage, performance, etc?

 

I dont know when it first got cut, but I havent noticed any change in anything. It might be hurting gas mileage or performnace, but if it is, it's a negligble amount and I have not noticed anything different.

 

Ive also got 0901 (awaiting pay day for a replacement) does anyone know if with this code (for the heater) if the ecu operates in open loop (or closed i dont remeber which pertains to our cars) or does it still read off of that sensor even though the operating temp isnt being controlled? im also assuming there will be a decrease in gas mileage and performance...correct?

 

Per the Haynes Manual, Heated oxygen sensors are used on some models to allow the engine to reach the closed loop state faster.

 

u kbow u gotta ask local first son.....hey u free tomorrow i can get that filter finally

 

Thats all it is. If the O2 sensor actually failed, you'll be getting an 0503 code. Just connect the wire and you should be set.

 

Where are all these codes read from?

 

http://forums.maxima.org/showthread.php?t=104931

 

Yea I'm free tomorrow, pm me on ubrf and you can stop by or something.