I have a 2000 D2 that is setting a code for the passenger upstream O2. I replaced the sensor twice and same. Looking at the scan tool as soon as it starts up the reading for the O2 goes from half a volt to zero and remains there (the drivers O2 cycles). If i unplug the sensor it remains at half a volt. I have load tested the wiring to and from the ECU, checked power and ground to the computer. At this point i think i am left replacing the ECU.

Any similar issues out there before i deal with ECU replacement? Any one repaired a driver issue like this?

Thanks

 

Have you swapped in a known good sensor? Perhaps from the other side?

 

I replaced that O2 twice just to be sure considering parts quality now. Although, two bad out of the box isn't out of the realm.

 

When troubleshooting always try to test using known good parts.

 

Where did you get the sensor and what brand is it?

 

First replacement was a Walker from Atlantic British via Amazon
The second was a cheap "A-Premium" from amazon

 

Walker is pretty poor quality for these unfortunately. I had 2 die in less than 10k miles from Atlantic British. As Extinct recommended, I'd swap the good side to the bad side, and see what happens so that you can isolate the problem further.

I would return both your Walker and A-Premium sensors as Defective, definitely don't eat that cost.

 

Swapped side to side. Yep, two bad sensors right out of the box. Unbelievable. I thought walker was the good brand.