I am pulling up this code and not sure which sensor I should replace thats all my OBD is reading.

I do not wanna buy both so I need to know which one is the correct one. Front or Rear?

Thanks!

 

P0141 = secondary O2 sensor heater circuit

That's the rear sensor, mounted in the catalyst. But that code doesn't necessarily mean the sensor itself is bad.

Got a multi-meter? Unplug the sensor and find the 2 same-color (black?) wires on the sensor-side of the plug. Measure resistance between them - it should be 10 to 40 ohms. A bad sensor will usually be open-circuit (no continuity).

If the sensor is OK, then you need to look at wiring problems in the car.

 

Thanks I will try and do that