Aveo "Hold" flashing, Code P0128 Pending still there. (Already changed thermostat.)

New member here, I own a 2009 Chevy Aveo LT. I recently had my "hold" icon flashing. I had done some research about this issue and came across useful information, but not enough. As other members have had this same issue stating it was the thermostat, I went forward and changed that out this evening with an OEM part. I topped of fluids, as my coolant overflow or reservoir was low. I had let my car idle for about 10 minutes trying to get the system to "Burp". My Gauge is still not functioning and the "Hold" icon is still flashing. Car also still has a pending P0128 Code. Has anyone else run into this problem? Or have an idea of what else could be wrong? I have not taken the car for a ride yet.

Thanks.