Hello, I need some help trying to fix some sensor codes on my car. I ran a computer test and it gives me P0156 and P0161. I'm not sure what i need to do next to fix the problem and get the check-engine light to turn off. I already replaced the 02 sensors, but the codes keep coming up after i have already cleared them once.

Any suggestions?

 

You've got a problem with the heater circuit in the O2 sensor after the CAT. The PCM monitors this circuit all the time, but calls on it during cold starts. The O2 sensor has a small heater in it to raise the O2 sensor temperature quickly during cold starts. The O2 sensor should have 4 wires, 2 are related to O2 signal to PCM and 2 are heater circuit (I don't remember colors). Check a wiring diagram for correct wire coloring - check for 12v power and ground on the heater circuit. Most of the time I find a wire damaged from road debris hitting under the car or wire damaged from hot exhaust. Also, check fuse for heater circuit - if wire melts and shorts on exhaust pipe, it will blow a fuse.
Good Luck,
Corky