where is the fuse for the heater circuit? I would like to check into that



is it possible to check the o2 sensor itself?

or to try the pinouts at the sensor plug?

my code reader can read live data, and mreo than I know what to do with

 

It is very possible you got a bad O2 sensor right out of the box. If you can read live data, check the O2 sensor output from a cold start. The pcm will question whether the heater is working if it takes too long for the O2 sensor to start providing good data. The heater is in the sensor to heat the element so that the pcm can go into closed loop faster which lowers emissions, increases mileage, protects the catalytic converter, etc... You can test the heater circuit by unplugging the sensor, finding the pinout on the connector and measuring for 12 volts at the heater pins with the ignition switch on. No voltage or low voltage means the heater won't work. Unless you were getting this code before you changed the sensor I would say you either got a bad sensor or you may have pulled a pin or 2 out of the connector while installing the new one.
Oh, you did get a direct plug-in replacement sensor right? The generic, one size fits all sensors are junk and shouldn't be used unless a direct plug-in replacement can't be found.

 

bad o2 out of the box? how common is this? this is very disconcerting to me.. my lancer also has a p0135, and it's first o2 sensor is on my list of things to replace, however, I have over 103k on it, and it is still getting a combined 27 mpg

can I test the output with the code scanner? or the heater circuit part of it? or will I need to actually use a voltmeter underneath the car at the sensor? which pins would I need to check if the later?