Oxygen sensor question(s)

[frisco]

Hey all,

For every vehicle I owned past and present, I have never had to change the o2 sensor. I know they throw a code when it needs to be replaced.
I'm curious if it makes sense to replace even though I don't have a CEL? The o2 in my crv are OEM. The previous owner, my father in law, said he never touched them. The CRV is 2005 (199800 kms)so almost 19 years old. Would I get better gas mileage if I purchased a new sensor? Or just wasting money?

Thanks.

 

[edyvw]

Hey all,

For every vehicle I owned past and present, I have never had to change the o2 sensor. I know they throw a code when it needs to be replaced.
I'm curious if it makes sense to replace even though I don't have a CEL? The o2 in my crv are OEM. The previous owner, my father in law, said he never touched them. The CRV is 2005 (199800 kms)so almost 19 years old. Would I get better gas mileage if I purchased a new sensor? Or just wasting money?

Thanks.

You should have two sensors. Upper stream and lower. Always change all sensors.

 

[Nessism1]

FUF = Forget Until Failure

 

[BrendanC]

i personally do not change them until a CEL is thrown. the car tracks how they respond.

 

[SC Maintenance]

No need. You won’t get better mileage. They’re monitored and if they get out of whack you will get a code. You could always monitor your LTFTif your concerned.

 

[LazyDog]

The first one or upper one is not a O2 sensor but air fuel ratio sensor/ AFR much more expensive. Just leave them alone until you get a code.

 

[wtd]

O2 sensors can get lazy over time and usually won't throw a code until they are dead, almost dead, or whatever the criteria is for that vehicle for setting a CEL. The only way to know if they are switching correctly is to monitor them in live data. The pre-cat ones should switch fairly rapidly between 150 to about 850 milivolts at idle in closed loop. Lazy O2 sensors can affect gas mileage.

 

[edyvw]

O2 sensors can get lazy over time and usually won't throw a code until they are dead, almost dead, or whatever the criteria is for that vehicle for setting a CEL. The only way to know if they are switching correctly is to monitor them in live data. The pre-cat ones should switch fairly rapidly between 150 to about 850 milivolts at idle in closed loop. Lazy O2 sensors can affect gas mileage.

^This. Some manufacturers set very low criteria, and O2 sensor needs to be dead to throw CEL. On BMW’s any small discrepancy, and CEL will lit. I got O2 CEL at around 130k on my 328. Delete it and didn’t come back. But I still replaced all 4 sensors.

 

[frisco]

Thanks to all that replied. I will just wait for a CEL to appear. I don't have a special scan tool that reads live data. Wish I had one lol.

 

[RAR]

Good idea.

Just leave them alone until they pass away on their own. Then you can wrestle with removing them from their 19 year home.

 

[burbguy82]

Unless data from a scanner tells you, or CEL, leave them alone.

 

[SHOZ]

I changed out the OE primary one on Accent at about 100k, just because. Put in a eBay Bosch. It lasted 50k and I put the old OE back in for another 20k. Finally got another OE and had to replace the second one too. The second one was quite the pain to do as it stripped out the treads on the pipe when it came out.

I use the free Torque app and the Hyundai EX app, that cost a couple bucks with my android phone. It needs a bluetooth OBDII dongle which the better they are the faster they work. But cheap ones will do the job for basic data collection.

My Gen Coupe Torque screen. This looks like at deceleration in gear..