Hyundai Repair: 2003 sonata alternator, wont move, system voltage

Question
i just sent a question and wanted to add on that the speedometer keeps getting stuck at 20 mph and the rpm wont move is that a ECU problem?

Answer
Since we've established that you have a system voltage issue in the previous question, you should fix that first.  Electronic devices will not work properly when the voltage is below a certain level.  It's possible that replacing the alternator will resolve all the issues.