How long should an O2 sensor last?

[BJM]

For everyday driving how long should my O2 sensor last? When I bought the car 4 years ago I replaced it because I didn't know how old it was. So now my sensor is 4 years old and I think its starting to get lazy and I think the lowest values I see on my Scanmaster are slowly getting lower. Is it time to replace it?

 

[2QUIK6]

Its the O2 cross-counts that will tell you if its getting lazy, they should cycle from 0-255 in less than 90 seconds.
Its been my experience that if you bought a Bosch replacement, then they do not seem to last very long, maybe 15-30k miles.
Always buy an AC Delco replacement, they will last much longer. If you don't use any leaded fuel, they should last 40-50k miles or more, a heated unit will last even longer.
I've never actually had an AC one go bad yet without running leaded fuel.

 

[BJM]

I don't use any leaded fuel but my Direct Scan readings seem to show the O2 sensor used to dip down to .09-.12 V normally and now its slightly low like .04-.08 V on the bottom end. I didn't have a number for cross counts and while its still pretty good I think they have slowed down some.

 

[galoush]

If theres any question for the $$$$ Change it , id recomend the Denso , works great with 116 race gas so im assuming if it will live with that stuff it would last Lonnnnnnnngggg with pump stuff.

 

[BJM]

I called around town and nobody carries the Denso stuff, only Bosch. Where can I buy the Denso?

 

[Randy Greenoe]

Originally posted by BJM
I called around town and nobody carries the Denso stuff, only Bosch. Where can I buy the Denso?

www.sparkplugs.com

 

[bruce]

Originally posted by BJM
I called around town and nobody carries the Denso stuff, only Bosch. Where can I buy the Denso?

I'll stick with ACs.
If it's still doing cross counts, that's all that matters, it's just used as a switch to detect stoich.. .00012993899384394mv or, .35v it's the same to the ecm.

 

[2QUIK6]

Originally posted by BJM
I don't use any leaded fuel but my Direct Scan readings

On Direct Scan, it is displayed on the "text" format as "O2 X-cnt" should cycle from 0-255 and then start over, and over, should do the complete cycle in less than 90 seconds on a good O2 sensor.