What is the error code? If it is what i am thinking it is the Mass airflow sensor. Do you have any hesitation or loss of power? Any stalling? How many miles do you have?

If you take it to Autozone they might have a OBD2 reader to get the code if your check engine light is on.

But my bet would be the MAF sensor, since I got the "bank 1 sensor 2" code p0171 i think... and it was the MAF.

If that is is it is about $70 plus core for the part and easy to replace. Located to the left of the air filter housing on the intake tube. Remove two screws. disconnect wire harness.

 

decru makes a good point, many times a CEL indicating a potentially bad O2 sensor is actually just a dirty MAF sensor. Many have reported good results with just cleaning the sensor and attached IAT (intake air temperature sensor). They make MAF safe solvents out there - CRC brand is pretty decent. Brake cleaner works too - just make sure it is the non-chlorinated variant.

But to your original query. Bank #1, Sensor #2 is the downstream (post) cat O2 sensor.

 

Yeah i tried cleaning mine, but it still tripped the diagnostics. Expensive little thing, tell you that!

 

Autozones at my place does not help you diagnosis the error code. They will say, go buy the OBD scanner.

 

I just checked the history on my scanner and it was p0014 and 171 and it was b1s2 error. It was my MAF, I assume that is your problem.