for a possible code 16....

is there anything other than maybe a kanker on the harness to cause this ?
the complete opti is new.

would the corrosion be at the terminal end or throughout the harness ?

thanks,

 

Terminal ends would be the greater suspects. You would also want to be sure no corrosion is present on the terminals on the opti, itself. A corroded connector will transfer corrosion to the opti terminals, so both would need to be cleaned.