1996 Grand AM code 134 O2 Sensor

The check engine lite is on and computer says Code 134 Bank 1 Sensor. Checked voltage at O2 sensor on the single wire which reads a fairly steady .937 to .939 volts after engine is warmed up and doesn't fluctuate. Changed sensor with a Bosch #12014 and voltage still reads the same and check engine lite still comes on. The other O2 sensor by the convertor was changed about 10 months ago. Any suggestions!