Contour Enthusiasts Group Archives Forums General Troubleshooting Bad O2 Sensor but no CEL

I think my Bank 2 O2 Sensor 2 is bad but there is no CEL. The voltage on the sensor from the OBD-II software is a relatively constant 0.03-0.04 V. All other fluctuate as expected. However this does not generate a problem code nad CEL as it is still within 'limits'. At least it is an easy one to change.
Any insight? Why doesn't a relatively constant voltage on the sensor get picked up by the computer as a problem (Not programmed for anything but a voltage out of range?).