[RESOLVED] O2 sensor... Stumped...

[Gregory]

Ok, I had the o2 sensor housing switched, and with that, went in a different (used) o2 sensor. After it was all done, I saw my fuel trims where way up and my 02 voltage was way down (like .04-.06V). So I thought it was a bad o2 sensor. So, I put the other sensor back in, that I had thought was working just fine (at least last time I looked, and it was running fine). It did nothing for some reason. So I started tampering with the wiring harness thinking something must have gone wrong with that. I applied some current to the white wire that runs to the ECU to pick up the voltage, and the logger immediately showed this. I tested the red wire (which I think is the 02 heater wire???) and it gave me current, and if I directly connected the two, it would read fine. Could something be wrong with the grounds all of a sudden? Could my original O2 sensor also be bad? I mean, what are the chances? I was also informed that the newer o2 sensor was working before (when I bought it with the housing). I don't know what to do now? Buy a new o2 sensor? That just seems like a long shot. Please help me out if you can. I tried to research as much as I could before making this post.

Best,
Greg

 

[Gregory]

Does anyone know what the o2 voltage should be reading when the car is off, but the key is in the on position? 0.00V?

 

[1992awdlaser]

According to dsmlink mine was reading 0.00v with the key on engine off. It read 0.00v-0.02v while cranking.

 

[gsx951]

https://www.automedicsupply.com/index.php?

 

[Gregory]

I realized I never closed this thread. The problem ended up being that somehow the new (but really used) O2 was bad, and I guess my previous one just happen to go bad extremely close to the time I was having the new one put in. I got a new 02 and it fixed the problem. I almost don't believe that it happened. Makes me think that something caused the o2 sensors to foul out.