where is the obd2 port located

Under the steering column.

Fault codes never say to replace parts. They only tell you the circuit that needs further diagnosis. The sensor will indeed be the cause about half of the time, but there's a lot of other possible causes for a fault code to set.

ive looked all over under and i still cant find it ...i took it to the mechanic a while back also and they told me i had to change it.i just dident think it was very important until yesterday morning when it dident pass the test and it was cause of that

That plug is always right under the steering column, above the brake pedal.

What is the problem or symptom? Did the mechanic tell you a description of the fault code? Have you tried displaying the codes in the odometer readout? Codes for problems that can adversely affect emissions must turn on the Check Engine light. Has yours been on?

The part in the photo you posted looks like a crankshaft position sensor but not for your engine. The engine won't run if that sensor is bad.