What does it mean to get a fault code out of Port 1?
 

Hi Enthusiasts,

I have a 1995 850 SE, and the tech manual talks about getting codes out of "Diagnostic unit A output socket No. 2" for the fuel injection system, and "socket No. 6" for the ignition system.

Poking around, though, I could see a female socket/contact in socket No. 1. Plugging the test lead into there, I got a 2-2-3 code... but the manual doesn't say anything about socket No. 1.

What system is issuing that code then?

Idle air control valve signal absent or faulty