i have an auto 92 ls. i just cleaned out my IACV then took it for a drive i got a couple blocks down from my house my check engine light came on and the S3 box started blinking when i had it in drive. i stopped at a buddies house to check it out, turned my car off, then turned it back on. the check engine light turned off but the S3 box keeps blinking and my speedometer was working. what happened?

 

someone please help me out! this is my daily driver!

 

Make sure that the plug from your engine harness that goes to the transmission is actually plugged in. This located towards the rear of the tranny behind the starter.