I replaced the catalitic conveter yesterday and now I've got a check engine light. The computer code is P0141-- O2 sensor heater circuit malfunction. Could it be something other than the sensor?

 

Did you pull the connector back apart and make sure the pins aren't corroded/damaged (poor mating terminals) or pushed out? Wiring as well.. The code is for the 'heater circuit' for the Bank 1 Sensor/monitor 2 (12) Not a cat/system efficiency...