P0141 is for the heater circuit of the 2nd sensor. Two of it's wires are the same color (black?). Once you figure out how to unplug the sensor, measure the resistance between those 2 same-color wires of the sensor. It should be between 10 & 40 ohms.

If that's OK, then the problem is in the wiring of the car. Find the 2 wires that correspond to those 2 (don't know what colors). One should be hot (battery voltage) & the other should be grounded when the engine is running.