02 Sensor issue

[Saibomb]

Hello,

A couple of months ago my service engine soon light came on and so I went to get it checked out. Apparently, my 02 sensor had "high voltage" and a "slow response time" (The codes were P0138 and P0139). And this was for Bank 1 Sensor 2. I'm going to take it to my cousin's shop to get it fixed, but I've heard a lot of mechanics have mistakenly replaced the wrong sensor so I would just like to check with some of you here who have more expertise with these sorts of vehicles to make sure I buy the right sensor and have the correct one replaced. Oh, and my car is a 2000 I30

[Q45tech]

BANK number and SENSOR number says it all to any trained certified technican!

Using a MECHANIC instead of a TECHNICAN is owners fault!

[Saibomb]

I spoke to my cousin and he said it isn't worth replacing because this issue always reoccurs with Maximas/I30s. I'm wondering what the risks are for not changing the 02 sensor are, because honestly, if it's not necessary I'm not sure if I'd want to replace it.

[Q45tech]

The first O2 sensor is used by ecu to optimize AF, the 2nd O2 sensor is used to test viablity of cat convertor [nothing else].

Always keep the primary O2 fresh [V8 have 2 of each], the secondaries are for emission testing only.

By now a 2000 I30 should [might] be in need of fresh cats as the longevity is not what it was back in 90's. The 2002+ versions are even cheaper and less robust.

[Saibomb]

Oh I see, then there's really no point in replacing it I guess.

Now, if it was the first sensor, then it seems like it would be wiser to change it.

Oh, and my car only has 80,000 miles on it. Were you thinking my car had more miles on it (say over a 100,000?) and thus you thought I may need to change my cats soon? I don't know too much about cars but I would think a part like that wouldn't need to be replaced after only 80,000...

[goody90q45]

We Q45 owners have trouble with leaky and dying injectors which sends unburnt fuel through the exhaust and takes the cats to an early death. It's always best to replace O2 sensors in pairs and even better to replace all 4 at the same time to get a fresh start. If your gas mileage is down just one or two mpg from what you used to get they'll pay for themselves quickly since the engine will be running more efficiently.