It says in the manual that 88- up carsaren't supposedto use the extra single wire connector but my car has it?
It's a 91 mustang gt the EEC test i believe is on the drivers side shock tower. Am I supposed to not use that and just use the main plug on the scanner? Also are the 91 codes double digits or triple digits? thanks

 

All '86-'93 systems are 2-digit types....the single wire is the Self-Test Input (STI) for the system to initiate the self-tests......it should be used....'81-'83 MCU systems are the ones that only use the big connector.

 

ah ok thats what i thought and have been using it like that.