Throttle position control Fault

[Hack213]

Hey guys own a 2008 x5 4.8 96,646 miles . A week ago I got the valve cover gaskets and spark plugs done with a friend , picked up the car 3 days later and was driving smooth on the 4th day on my way home from work car went to limp mode and I quickly connected my obd 2 pocket scanner and got this code p1637, I shut off the car and waited a minute turned it back on and the car drove fine.
I hooked it up to the x5 to my laptop scanned it with rheingold and nothing came up anyways since then I haven't driven the vehicle afraid to have it go to into limp mode ;(

Previous work done throttle body harness and gas pedal and throttle body changed.

P1637 11505 Throttle position control – control deviation, bank 1 Wiring, throttle motor position sensor, ECM

I read about the harness being shorted out but I'm not sure where to start anyways thank you guys!!