Hello, my name is Chris. 1. Check for a 5-volt reference on the Orange/Green wire with the sending unit unplugged and a good ground on the Blue/Yellow wire. If no 5-volt reference, check for an open or shorted wire between the Engine Control Module (ECM) and the sending unit. 2. Check resistance of the sending unit, it should range from 80 ohms full - 290 empty ohms.
The codes must be cleared after repairs, to get the gauge to start working.
Cleared the codes and that did the trick.
Sounds good, glad I could help.