[Young_Man]

Who has the best prices on O2 sensors? I'm looking to replace all of mine.

[mweisdorfer]

I would not replace them unless you get a fault code. I could sort of see it as preventative maintenance if you were say over 100k, but even then it's a stretch.

I have 110k on my N54, and they work just fine. I have ran a few checks on them earlier this year.

You can get a Bosch parts app for free on android and iPhone. Use Bosch O2 sensors. They are OEM. I have read the O2 sensors are not real fun replacing on the n54 motor.

Amazon should carry all 4 of them. eBay is another place to get them, but make sure you get them from a reputable dealer. You can save some money by going with universal Bosch sensors for down stream. They are typically around $50.00 each vs $90 to 100, but they are not plug and play; you will have to do the wiring.

Probably gonna be spending about $300-400.00 for all 4 depending if you get the universal O2 sensors for the downstream or not.

[Young_Man]

I got these 2 codes yesterday. (2C31 Lambda probe in front of catalytic converter, trimming control) and (2C77 Lambda probe behind catalytic converter, signal).. I think there may be more problems though because my car wouldn't build any boost and I also got a (30FF boost under target) code. I'm checking all connections and vacuum lines when I get off.

[DLam]

i bought my replacement o2 sensor on ecstuning. i got the bosch ones

[Young_Man]

Are the primary and secondary O2 sensors the same other than cable length? I found both on Amazon for a little over 100 dollars.

[rmz]

rockauto.com Just got all 4 for good prices, BOSCH/OEM branded.

[ucdbiendog]

Originally Posted by mweisdorfer

... I have ran a few checks on them earlier this year.

what checks did you do?

[Jklad]

Bavauto had the best price I could find for Bosch 02 sensors. I'm at 114k and replacing only the fronts as preventive maintenance, plus I have some funky occasional stutters going on and my gas mileage has sucked for a while and am curious to see if it will help.

[mweisdorfer]

You have 2 before the catalytic converter and 2 after the catalytic converter. Typically you replace them in pairs. So, if the O2 sensor for banks 1-3 before the catalytic converter goes bad, then you should replace the O2 sensor for banks 4-6 before the catalytic converter too.

It sucks that you have one gone on each side of the converter. Now I know why you want to replace all 4. Yes, I would probably replace all 4 too.

What year is your BMW? The part numbers are different for the N54 and N55 motors. I would think even for an N52 as well..

I can get all 4 on Amazon for around $260.00, but that's with getting 2 universals for the post cats.

[mweisdorfer]

I have a actron cp 9580a scanner. It can measure voltage of the O2 sensors. You can tell by the amount of voltage and frequency of such voltage (steady or jumpy) if one is bad.

[Young_Man]

2008. I'm mainly worried about the primaries. I'm running catless downpipes so I wasn't really too concerned with the others.

[Young_Man]

If I'm replacing just my o2 sensors before the cat I order one grey and one black right?

[mike@x-ph.com]

We offer OE parts and price match any competitor

[mweisdorfer]

Originally Posted by Young_Man

If I'm replacing just my o2 sensors before the cat I order one grey and one black right?

You need part numbers before you can order them

[Young_Man]

Bosch 17098 & Bosch 17099

[mweisdorfer]

Originally Posted by Young_Man

Bosch 17098 & Bosch 17099

http://www.amazon.com/Bosch-17098-Ox.../dp/B000JZGEWE" rel="" target="_blank">http://<a href="http://www.amazon.co...B000JZGEWE</a>

http://www.amazon.com/Bosch-15733-Ox.../dp/B000BZG8ZU" rel="" target="_blank">http://<a href="http://www.amazon.co...B000BZG8ZU</a>

http://www.amazon.com/Bosch-17099-Ox.../dp/B000JZCYWI