No accelerator/throttle response

Hello, cadillac people. This is my first cadillac experience and I need some help. I was are certified back in the 80's&90's but I just bought a 2005 cts with a accelerator/throttle issues.there is no throttle response! It cranks up and idles fine, it'll run all day long. I can put it in gear and idle all over the parking lot but no throttle press on the accelerator and nothing happens stays at idle I've replaced the accelerator pedal position sensor, twice, the throttle body assembly, twice, and the ecm, once. And it's still the same. I've checked the 5.v reference wires I have 4.9 v.

The signal wires fluctuates smoothly when pressing on pedal. I keep getting the same 2 codes 2122, and 2127 accelerator pedal position sensor circuit 1 and 2 low voltage.

I am lost as to what the problem is! Also when you turn the ignition on I can hear the throttle actuator motor running, moving the throttle! I tried several relearn procedures, to no avail! Can someone tell me what I'm missing, please help!