P0136 code

Question

For my 04 Hyundai elantra the troubel codes: P0038 and P0136 came up and I have no cule what they mean or what problems they are causing and how to fix it. I just need to know what they mean and if I can fix it. (I prefer not taking things to a shop if I dont need to) any help would be much appreciated.
Thanks

Answer 1

both codes are for bank 1 sensor 2 oxygen sensor which is most likely bad

the sensor is under the car near the catalytic converter.