As I was futzing around with my '02 WRX when I noticed a disconneted wire under my dash, behind the steering wheel. It has a lime green connector and was wrapped with blue e-tape. I think it had two leads in each connector and was of a super thin guage. T hought it was a relay coupled with a grounding wire. So I plugged it in. When I started the car the CHECK ENGINE LIGHT was going nuts. Has anybody else noticed this wire? And does anybody know what it does?

 

It is one of the test connectors for the ECU. I would onplug it and leave it alone. If you leave it plugged in the CEL will stay on. It works in conjunction with the OBDII port. I am not sure what it really does. If you look closely there is also a little white connector there too. It also does something for the Ecu during diagnostic tests.

 

Get familiar with this thread here:

https://www.i-club.com/forums/subaru-general-30/subaru-secrets-some-might-impreza-only-59578/

 

Thanks for the info!

 

It puts the ecu into a diagnostic mode which i think the Cobb access port uses to update the ecu info

 

that is so funny when i got my car i was looking undethere to pass a wire through for my amp and saw it and did the same thing with the same results hahaha, that is funny. but i have an 02 rs, so it has to be the same shiit.