SATURN COMPUTER NO COMMUNICATION

So I Am Having A Problem With The Ecm. There Is No Communication With It. I Have A Scanner And It Does Not Let Me Communicate With The Ecm...

My Check Engine Light Was On Three Weeks Ago. It Was Code Po440. I Replaced The Gas Cap And Air Filter. My Neighbor Replaced The O2...

All Gauges Jump Around. Abs, Engine, Etc. Lights Come On. Engine Goes To Limp Mode. No Communication From Vehicle To Obdii Scanner.

I Have Checked All Grounds And Replaced The Throttle Body. I Have Been All Over This Car But It Has Lost Connection With Tcm And Ecu And Has...