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'Diagnostic' means 1: concerned with diagnosis; used for furthering diagnosis; 2: characteristic or indicative of a disease
Passenger side fender near strut tower
in most hondas, the port in under the steering wheel to the left.
di·ag·nos·tic (dī'əg-nŏs'tĭk) adj. Of, relating to, or used in a diagnosis. Serving to identify a particular disease; characteristic. n. The art or practice of medical diagnosis. Often used...