Code P0141 in 2000 Honda CRV. Replaced (secondary) o2 sensor with no luck. Any advice?

I have a 2000 Honda CRV and I'm getting the P0141 code (o2 bank 1 sensor 2 heater circuit). I've replaced the secondary o2 sensor with no luck; I've changed the fuse (#15) under the dash; I've checked the two black wires on the harness going to the sensor with a test light and they both have power. However, I don't know how much they're getting because my multimeter broke (getting a new one tomorrow). What kind of power should I be getting to those two wires? Where should I go from here? Are there any other issues that maybe be causing this code to be thrown? I'm not very good at diagnosing so any help would be much appreciated.