Shifting issues

[turbo23]

The car goes into reverse,drive,and park, But when in drive is stays in high gear, even if i shift it my self. Another issue is that my snap-on scanner will not communicate with the ecm. the car runs great.

 

[Scrubulum]

Vague post but I will attempt a reply.
I am guessing the car is automatic.
Sometimes the overdrive locks out and doesn't retract. When this happens you are driving and come up to a stop light and the car will stall, like a manual when you don't push in the clutch. You can unplug the overdrive (there is usually a connector on the trans) and drive normally, you may notice a drop in fuel economy. The only real fix that I know of is a trans rebuild.
Hope that helps some. Post some more details and I will try to answer better.

 

[Spyderman7]

I've had 7 or 8 1g autos do what you're describing.I've never replaced a trans,solenoid or anything else under the hood.It was always the TCU located just to the right of the gas pedal,behind the carpet side panel of the center console.