Originally Posted by RichieST

It should go solid red when ignition is on, then go out a few seconds later. If it flashes fast then it's detected a problem.

Hold both keys together and start it with whatever one turns in the barrel. That was it should pick up the pats signal from good key yet it will start with the other. If that works then just tape up the other key inside the plastic cowling to permanently de-activate the pats for now.