Oxygen Sensor Questions

[chasreina]

My 2003 infiniti i35 needs two oxygen sensors replaced.
I know its the #2 sensor on the left bank and the #2 sensor on the right bank.

Ive been looking for the sensors online and wanted to make sure I ordered the right part.

On every parts site ive looked at there are choices for a 4-wire, 3-wire, 2-wire or 1-wire oxygen sensor.
What is the difference between the number of wires if they are all made for a 2003 i35?
I will not be replacing these sensors myself by the way.

Also, which sensor do i need for the specific location on the engine bank.
Some of the parts pages include location, such as "after catalytic converter", "Rear, Driver And Passenger Side", and "universal". Im not too familar with these terms and my mechanic does not speak too much english.

I dont want to buy the wrong one could someone please help clarify which sensors i need exactly. Thanks.

[MTZI30]

LOL dude i went through the same thing no my i30. DONT GET CONFUSED:There are "rear" 02 sensors that are located at the REAR of the pipe and there are DOWNSTREAM 02 sensors that are located after the cat. Click my name and check my old threads theres a diagram on there.

[MaximA32]

Two different engines MTZI30. You have the VQ30 while he has the VQ35. The wires are going to be different for his car than they are for yours.

OP, there are four oxygen sensors on your car. Two pre-cat and two post-cat. Which two are you replacing? Most shops will suggest that you replace all four at the same time and I agree. If you're going to have it done, may as well do the entire job. Also, check http://www.rockauto.com Their catalog is VERY easy to use and I've never had a problem with their service.

Welcome to NICO!

[chasreina]

Thanks for sharing the catalog.

Ok, so the "#2 sensors driver and passenger side" are the "post-cat downstream sensors".
Is this correct?
Maybe I will replace them all but I would still like to know which ones are making my service engine light come on.

Again, do I need to worry about the number of wires on the sensor when purchasing???

[MTZI30]

Two different engines MTZI30. You have the VQ30 while he has the VQ35. The wires are going to be different for his car than they are for yours.

OP, there are four oxygen sensors on your car. Two pre-cat and two post-cat. Which two are you replacing? Most shops will suggest that you replace all four at the same time and I agree. If you're going to have it done, may as well do the entire job. Also, check http://www.rockauto.com Their catalog is VERY easy to use and I've never had a problem with their service.

Welcome to NICO!

Ah i just assumed nissan was like ford in the fact that theyll use the same stuff for a lot of different engines.