Hey guys, I need help fixing my 03 G35 sedan the car is throwing a P0031 Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 1 Sensor 1). Can anyone tell me what this means and how I can fix it?

Recently had anything replaced or mods installed?

OP whenever you get codes like this.....there are multiple things it could be. I would check your 02 Sensors and make sure you dont have any frayed wires. Next I have seen people stating a faulty ECU as well. with that being said just start with the 02 Sensors and most likely thats the culprit. Like James has stated above have you installed any mods recently or done anything to the car?? I am in Mckinney and I could take a look at it if you need help as well for a smaller fee than what a shop would charge. 2124-282-2711 is my cell.

I have not installed any mods recently but I did get my belts and front brakes changed recently. The only mod that is on the car is the motordyne basic plenum spacer but I installed that like last summer. What I had planned on doing is replacing the heated oxygen sensor on the passenger side and see if that fixes it.

Well I got everything unplugged and ready to come out except that the O2 sensor was so tightly bolted on the car that I could not get it loose. On top of that I did not have enough room to even try it with the air ratchet. Is there some kind of trick to getting this sensor loose?

O2 sensor socket and a breaker bar. Bank1 sensor1 is driver side upstream sensor.

Bank 1 is passenger side and there is no room for a breaker bar and I am using an O2 socket.

Are you sure about the bank? Nearly every car I worked on that had a V-configured motor, bank 1 is driver side.

I got all 4 of my sensors out of my car with a breaker bar and an O2 sensor socket.

https://g35driver.com/forums/engine-...nger-side.html

Yes its the passenger side. What did you take out to get a breaker bar in there.

It's been a while since I did it. I think I disconnected the top end of the cat from the manifold and let it hang down a bit. Back two were ez to get to. The top two needed just a hair of finesse.

The code was telling me that the "top one" on the passenger side needed to be replaced. I have no idea how to get breaker bar or my air ratchet on it to get it loose. Also, today the MIL turned off and started driving with a little differently what does that mean?

You should take your car to g35man04...he's right up the street from you, sure he'd love to help you out

I agree compared to my old integra this car is kind of a beast to work on. I will send him a PM and see what he has to say.