Should I replace BOTH of my oxygen sensors? No engine codes...

[m4gician]

Hey everyone,

From the research and articles i've looked at, many people say Oxygen sensors should be replaced periodically (every 160,000km). They improve fuel economy of done, etc.

My care has two oxygen sensors. I haven't received any codes about them, or even relating to what could be an o2 sensor problem.

Should I replace either? Just one? (Which? up or down) or both?

Let me know RFD. Is the gain in fuel economy or performance worth it?

[001Stunna]

lolz dont replace em if they aint broken man, and even if u do DO NOT BUY EM LOCALLY. Can get them much cheaper online...much much cheaper.

However, if you want, pass by one day(around davenport/caledonia area) and ill read your ecu and see if they're working properly or acting lazy or w/e, plus ive been meaning to shoot you a pm regarding some detailing things if you're still doing it.

[m4gician]

lolz dont replace em if they aint broken man, and even if u do DO NOT BUY EM LOCALLY. Can get them much cheaper online...much much cheaper.

However, if you want, pass by one day(around davenport/caledonia area) and ill read your ecu and see if they're working properly or acting lazy or w/e, plus ive been meaning to shoot you a pm regarding some detailing things if you're still doing it.

Thanks for the tip man, I've always ordered my parts online, they're 50% off or better online. OEM o2 sensors are down from $240 US ($300 cad) to $100 USD. I may go with universal ones for less, but meh, OEM is plug and play.

If they won't affect performance, I won't replace them. But I need to see if RFD has a more experienced opinion than mine.

[001Stunna]

Thanks for the tip man, I've always ordered my parts online, they're 50% off or better online. OEM o2 sensors are down from $240 US ($300 cad) to $100 USD. I may go with universal ones for less, but meh, OEM is plug and play.

If they won't affect performance, I won't replace them. But I need to see if RFD has a more experienced opinion than mine.

Well your front o2 sensor is there to work with air/fuel ratio and should range from about 0.1-0.9volts. Usually if looking at a graph it usually goes 0.3-0.7v.

Your o2 in the cat is there to tell the ecu how the cat is performing and if its doing its job. Its voltage should be more stable and shouldnt have much variance.

If anything though as i said ill shoot you a pm later on tonight with some other things and if things work out and i run into you i can read your ecu and see how the o2's are performing as well and you can sort of make up your mind a little bit more if u wanna change em or not.

[corrupt123]

$100 each for new ones and you have no codes?

You'd need to drive like a billion km to make back your investment on the almost non-existent fuel savings you'd get. Don't bother.

[Pete_Coach]

Do not replace them on speculation. If they work, they work. There is no such thing as "lazy". There is no such thing as "failing". It has failed or not, period. The front O2 sensor takes a pre-read and the back one ensures your converter is working. If there is a differential, then the CEL light will come on.
No performance gain with new sensors.

[maniacshopper]

in your console, is there an error code?
If there is, get an obdII reader.
if there's problems with co, oh, NOx, you've got either a fouled O2 sensor, fouled spark plug, running air fuel mixture too lean or too rich. Or maybe EGR is clogged.

[ES_Revenge]

Do not replace them on speculation. If they work, they work. There is no such thing as "lazy". There is no such thing as "failing". It has failed or not, period. The front O2 sensor takes a pre-read and the back one ensures your converter is working. If there is a differential, then the CEL light will come on.
No performance gain with new sensors.

I tend to agree. I think the days of replacing O2 sensors after x number of miles are over. These days they can last quite a while and you'll never have a problem. I don't think you'll do any harm in changing one or both (unless you replace it with some made-in-China sensor, lol) but I don't think you need to replace it if it "ain't broke".

[Anonymouse]

Unless you get a code, I'd leave them alone. On the other hand, if you expect to keep the car for a few years, at that mileage you're going to have to replace them anyway and you may as well do it now.

[theguyz]

I disagree while the famous O2 sensor replacement was for savings on gas which was minute, a bad/faulty O2 sensor can make your car run horrible and cost more down the road for repairs caused by a bad O2 sensor.

If its not throwing codes, and your not at replacement km's i'd suggest just removing and cleaning them. They could have some carbon on them and cleaning them may increase lifetime.

[ottofly]

I disagree while the famous O2 sensor replacement was for savings on gas which was minute, a bad/faulty O2 sensor can make your car run horrible and cost more down the road for repairs caused by a bad O2 sensor.

If its not throwing codes, and your not at replacement km's i'd suggest just removing and cleaning them. They could have some carbon on them and cleaning them may increase lifetime.

I would not recommend that. Sometimes, taking an O2 sensor out and putting it back in may result in a code being thrown not to mention the risk of breaking a wire or stripping the threads. If fuel economy is stable with no suddden increase in consumption and no code is displayed, then I wouldn't touch them. My '98 civic has the original sensors and the car has 230,000km. O2 sensors can go a long way before they need replacement.

[ShadowVlican]

Do not replace them on speculation. If they work, they work. There is no such thing as "lazy". There is no such thing as "failing". It has failed or not, period. The front O2 sensor takes a pre-read and the back one ensures your converter is working. If there is a differential, then the CEL light will come on.
No performance gain with new sensors.

plenty of threads in subaru forums regarding lazy O2 sensors

[m4gician]

Thanks for all of the info guys, i wont be replacing them then. Haha. As for cleaning them, I'm told (and have read) have to clean them by heating them to burning off deposits?

[Qube]

O2 sensors should be replaced near the 160k mark depending on the car. If your car will throw a code for it then go ahead and hold off a bit. The worst case is it's dead and kills your cat converter... then you're talking big bucks. This is one of those things that could be preventative maintenance like fan belts and fuel filters.

[jetway1212]

Do not replace them on speculation. If they work, they work. There is no such thing as "lazy". There is no such thing as "failing". It has failed or not, period. The front O2 sensor takes a pre-read and the back one ensures your converter is working. If there is a differential, then the CEL light will come on.
No performance gain with new sensors.

I guess you have never tuned cars. Having a fully programmable ECU with onboard datalog is awsome, it can tell you lots of thing you dont know.

OP, when in doubt take it to a shop who can read more than error codes. Not all errors throw a CEL.

Not sure what car you're driving either.