About 2000 miles ago, I had a CEL. Checked the codes, I had a rear heated O2 sensor code. I cleared the code, bought an O2 sensor, and haven't had time to install it. I haven't noticed any problems since the CEL, and my gas mileage is fine. So the other day, I checked the codes again to see if there was a KS ghost code or anything similar, and I got 0505. So, the question is: is it possible that the O2 sensor is OK, and it was just having a bad day when it tripped the CEL, or once I cleared the code, did it stay clear for good? I would think that if the O2 sensor is bad, it would trigger the CEL again and store the DTC in memory right? What do you fellas think?

 

How many miles are on your car? It is recommende that they be changed after 100K miles.

 

I did the same thing and my CEL came back on after I drove for a little while longer so I have to change mine out... We should only use oem ones right? So that is bosch or does it not matter?

 

i have a little over 65k on it now... i'm the second owner...

i have a walker replacement that's waiting to go in. i might buy 2 more and do all 3 at the same time and just "git 'er done"

 

One of mine crapped out at 89K so I replaced all. Clearining the code will just make it come back on later. They need to be replaced.

 

of course they go out. nothing is ever perfect like it should be.

 

I would recommend that you only replace your rear O2 sensor at this time, and wait on the other two. No sense in replacing parts when they do not need to be replaced. I got 140K out of mine, and was still able to pass the emissions part of the California Smog test even with my y-pipe. I initially failed the test, but this was due to 3 of my OBDII self test monitors not being ready (you are only allowed 2 monitors not being ready, if you have more you fail), and not becuase of the emissions. I do not recommend waiting as long as me, but I just mention this so that you do not prematurely replace parts. The reason I replaced mine prior to getting the car retested was that the OBDII monitors that were not ready were the catalyst monitor (rear O2 sensor monitors this one), O2 sensor monitors (this one is obvious), and EVAP monitor. I replaced them to get some of my monitors to kick in, as I figured that eventhough they were not giving me a code they were too slugish for the monitoring system. When I went to get the car retested the evap monitnor kicked in (I think that I did not give the computer enough time to give the O2 sensor monitors, and catalyst monitor a chance to kick in, but I was happy to pass the smog test) some of my emissions went down considerably, letting me know that it was time to change them. So I would say to only replace the 2 front ones if you get a code, if not wait until you hit 100k miles to put in the new ones.

 

mine came on yesterday said bay 1 dont know which it is but he cleared and hasn't come on since in bay 1 the closest to you lookin at engine or back one?