There are 2 sets. First is green/2 pin, second is black/1 pin.
Black connectors are "read memory". Green connectors are "Diagnostic". Key off, plug together Black connectors, turn key on (engine off), read code from CEL. There is no start code, if you have multiple codes they will just repeat.
To do Diagnostic check:
Key off, plug in Green connectors only.
Turn key on (engine off), push accelerator pedal to the floor (WOT), bring accelerator pedal back to half-throttle, release accelerator.
Start engine (move switch fron On to Start).
Drive for 30 seconds over 6mph.
Stop vehicle, place Trans. in Neutral, rev engine over 2500 RPM for 1 minute.
CEL will either blink out a trouble code or will blink steady indicating no problems.
To clear codes: After performing Diagnostic, without turning off ignition, plug together the Black Memory connectors for at least 3 seconds.