Back from Smog check- fail, P0136 and 0 volts on O2 sens.

[blackmax]

So, that's driver side O2 sensor post-cat. I've replaced the sensor, but the same code comes back after the ECU is done cycling. Hooked up a diagnostic to it....and it reads ZERO volts for that sensor. The other side is at .7 volts (normal).

Just curious, would zero volts tend to make you suspect there is a real problem with either the sensor or the cat, or more likely that there is just a problem in the wiring? Seems like a real problem would be either higher or lower than than .7....but not zero. ?:shrug:

Also, my driver side cat was right on the edge of failing (100 ppm HC). Think that's its own problem an totally independent or part of the "mix" that's causing the P0136 and the zero volts?

 

[BOSMECH]

I would ring out the wires going to the sensor from were you plug in your OBD scanner also double check that it really connected