Accelerator pedal position sensor

I got a code P01238 accelerator pedal position sensor. The car went into limp mode and I took it to the dealer and they could not fix it. Because the pedal with sensor had been discontinued. So I replaced the pedal with a aftermarket pedal. I am still getting the same code P02138 and the car still enters limp mode.
I've tried 3 pedals and I also replaced the throttle body with sensor. I did a hard reset for the computer. It's still getting the code and going into limp mode.
How can I test the wires and pedal (It has 6 pins).