E1 pin? Diagnostic port

[nissky]

Hello First post here.

Any ideas on why the E1 diagnostic pin in engine bay would have a cable plugged in and run somewhere into the cabin?
As far as i can tell the E1 is just a ground connection, but there must be more to it...

The car is an mr2, by the way.

[nissky]

Nevermind my mistake it was plugged into the oxygen sensor output for the air/fuel meter, removed now.