Hyundai Repair: P134- o2 sensor, hyundai accent, oxygen level

Question
QUESTION: I have got the p134 error when checked my hyundai accent GLS 1.5 2001 model. It says 02 sensor CKT no active ( Bank 1 sensor 1). I want to know the functionality ,the location of this sensor and impact to the car.
ANSWER: The purpose of this oxygen sensor is to provide feedback on the oxygen level in the exhaust to allow the ECM to fine tune the fuel mixture for optimal emissions.  If left unrepaired, the car will typically continue to drive normally, but will likely experience a drop in fuel economy and an increase in emissions.

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QUESTION: Please tell me the location of sensor as well

Answer
The oxygen sensor will be in the exhaust manifold, above the manifold converter.  If it's not plainly visible in the top, it may be screwed into the transmission side of the manifold.  

My apologies.  I should have included this in my original response.