I gutted my cats about 3.5 months ago and installed O2 simms. I am now throwing a P1040 code which is bank 1 sensor 2 O2 sensor which would make it the driverside cat sensor. The simm is plugged in yet must not be working because the scan tool that Auto Zone used says "no activity". Any ideas guys?

 

I've had mine go bad & have seen others.

 

I've had one go bad every year for the last 3 years

 

mine are about 2mo old, had computer tunning......
hrtbeat2@earthlink.net

 

Mine read the same thing but it was just worked on. The reason was that the extension to the new header on the driver's side was put in backwards. Have you done any recent work that needed wires to be moved out of the way temporarily?