Rep Power: 0

My check engine light pop up a week ago. I took my 98 civic to get it scanned and the results brought a p0137, secondary sensor having low voltage, or something like that. I replaced the bad o2 sensor with an universal Denso o2 sensor. I read the instructions and I made sure that the wires were spliced correctly. After this, I disconnected the battery for about 10 minutes to reset the computer. A day later the cel popped up again. I'm thinking there is a bad wire somewhere after the sensor plug? What could be the problem?