1997 Hyundai Accent Oxygen Sensor Replacement

There is a pre-cat sensor and a post-cat sensor. The precat sensor is before the catalytic converter, usually in the exhaust manifold. You will see this one, when you open the hood and look down at the manifold. Should have 3-4 wires coming out of it. The post-cat sensor is after the cat, underneath the car. I'm assuming you read the code, which indicated it was the oxygen sensor? Make sure that there is no leak in the exhaust system, especially the exhaust flex pipe, it will throw sensors off and make them seem like they are bad. Make sure to use penetrating oil on the old sensor, as they are quite difficult to get out. Good luck