I just got done doing a rebuild. I have been driving the car around n/a for about 350 miles now. I have a datalogger so i was checking my codes. I keep getting an o2 lack of activity bank 1 sensor 1. I know this is the upstream o2 sensor. now, i pulled it up on the sensor data. the o2 sensor holds completely steady around .51 while at idle, it doesn't move. when i rev it or drive it, it works fine. the cel only comes on if i leave it idle for a minute or two when the sensor isn't changing voltage. is this a sign of a bad o2 sensor or something else?

Originally posted by nosdeclipse
is this a sign of a bad o2 sensor?

More than likely. Swap known good for bad if you're in a bind for money to make sure.

no where near being in a bind for money, just wondering what the problem might be. i just thought if the o2 sensor was bad that it wouldn't read at all.

Originally posted by nosdeclipse
no where near being in a bind for money, just wondering what the problem might be. i just thought if the o2 sensor was bad that it wouldn't read at all.

It's a heated element. It can get stuck in a certain range.

alright, thanks for the info. i just thought it was weird.

Actually, Bank 1 Sensor 1 should be your post-cat O2. Precat would be Sensor 0, unless your software is retarted.

Originally posted by etx
Actually, Bank 1 Sensor 1 should be your post-cat O2. Precat would be Sensor 0, unless your software is retarted.

indeed.

Originally posted by etx
Actually, Bank 1 Sensor 1 should be your post-cat O2. Precat would be Sensor 0, unless your software is retarted.

Not to disagree with you, but I have never seen the upstream referred to as Sensor Zero. On Snap-On MT2500 scanners as well as Genysis Scanners upstream is Sensor 1 and downstream is Sensor 2. :shrug

That is my experience.

mine reads, sensor 1 and sensor 2. sensor 1 is upstream. i really think the sensor is bad now. i was logging it today and it was stuck at 1.275v for about a minute and a half.