Hey guys,
I have been getting P3122(pre-cat O2 sensor short bank 1) code occasionally(once every couple month) so I just replaced O2 sensor last weekend. After installed the new sensor I drove about 30 miles and I had rough idle with SES light of course. It was hell of rich condition. I switched back to original sensor and it was fine. I contacted vendor and they said that I need to reset the ecu. Is this correct or BS?

The picture was after 30 miles of driving. New one on the left.

 

You need to clear the codes, not sure if this is what was reffered to as "reset ecu"

 

had similar issue, had a faulty new lambda so changed it for another one and all is good now (had to clear fault with durametric). mine never got really black like yours though i did 50+ miles with dodgy one in.

 

I cleared the code before install the new sensor. So it seems to be a defective sensor.