Read code P 0141 Install new sensor still reading code P 0141 Check voltage for sensor heater it is 12Vdc.

You do understand this is the Catalyst efficiency monitor, it is located after the catalytic converter..

Ask once and wait.

Did you check to see that the sensor heater circuit was providing proper voltage to the sensor when the engine is first started? Did you check for proper resistance in the heater of the sensor before replacing? Did you replace the correct sensor? Did you just have the code read and purchase a new sensor without confirming that the sensor was bad?

well why not check the voltage to the blower on high.
not 12v, then controller is bad.
if 12vdc is good the blower is bad.
easy peasy japanessy. (oops Korean South)
but Koreans are disgruntled Nipponese. LOL

the FSM shows how to remove it. ever seen one?
the Factory service manual.
or log in to alldata.com and just read that?

it sounds like a faulty oxygen/o2 sensor

Did they use an original equipment cat from the dealer or an aftermarket one? Aftermarket cats can cause more problems than they fix. There very few that I will personally install.

are they monitoring downstream O2 sensor data to see if the O2 sensor may be biased high? If the cat is doing its job the downstream O2 sensors will read a lower voltage. Tricking the vehicle into running rich or lean will cause this voltage to change ( unplugging a coil will cause the Downstream O2 to read high as the cat tries to burn off the extra fuel. Unplugging a fuel injector will cause the downstream O2 sensor to read low as extra air is being pushed thought the cats). Making sure the downstream O2 sensors are capable of switching should be part of the diagnostics.

Are you sure they replace the right cat? There are 5 different engine options for this car. If you let me know what engine you have I can let you know what bank is bank 1.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

that is a 12vdc power problem.
the sensors are failing , many do to lost power. (12vdc electrical distribution power)
so use a voltemeter, i bet even at he cig lighter port the voltage drops
below 13.3v running, way below. infact.
are your battery terminals clean,
is the rested voltage at the battery terms 12.6v (keys in pocket)
no? then the battery is being discharged,

I'm sorry you spent that money if this was the original code.

The code means one of the O2 sensors has a faulty heater or the power circuit for the heater is bad. The sensor is not heating up as fast as it should. Since you have replaced the sensor you would need to check the power circuit for the heater.

P0037 SUBARU Description Oxygen Sensors (O2S) or Heated Oxygen Sensors (HO2S) need to reach a minimum operating temperature of 750 degrees F to produce an accurate voltage signal. The faster the heated oxygen sensor reaches that temperature the faster the sensor will start sending an accurate signal to the Engine Control Module (ECM).

In order to achieve the require temperature, a heater element is included inside the heated oxygen sensor. The ECM controls the heated oxygen sensor heater element based on signals from the engine coolant temperature and engine load. The ECM controls the heater element circuit by allowing current flow to ground.

The ECM monitors the voltage signal received through the heater element circuit and determines the state of the circuit by comparing the voltage detected with the factory specifications.
Read more: http://engine-codes.com/p0037_subaru.html#ixzz26TjIZyLw

the sensor is getting to much power test and check all power connections and lines for damage /grounding or corrosion

P0108 - Manifold Absolute Pressure (MAP) Sensor Circuit High Voltage,
Possiable MAP sensor defective

P0134 - Heated Oxygen Sensor (HO2S) Circuit Insufficient Activity Bank 1 Sensor 1
P0141 - Heated Oxygen Sensor (HO2S) Heater Performance Bank 1 Sensor 2 , I recommend you replace both O2 sensors, bank 1 and bank 2