Where exactly can I find the output speed sensor on 2008 Hyundai Accent? A

diagram or picture would be awesome. I want to inspect and replace if necessary.

 

What trans is in your vehicle?
Most output speed sensors are on the rear of the trans.

Good thinking checking wiring and connections before jumping to conclusion of defective speed sensor.
If you had a simple multimeter you might be able to see if the sensor is putting out any signal at all before replacing.
All the code is telling you is, the computer is not seeing any signal.

 

I am not sure what trans it is. How can I find out?

 

There is usually a sticker on the driver's side door or door pillar with the trans code shown plus other info. You would need that code to determine which sensor in order to obtain the correct one , if needed..