What is the reason for the failure of the tp sensor of Buick's old Sail?

The throttle position (TP) sensor is a three-wire variable resistance sensor, which is installed on the throttle body and operated by the throttle shaft. The throttle position (TP) sensor is used to provide PCM with an electrical signal corresponding to the throttle opening. PCM uses this input number to calculate fuel injection quantity and ignition timing, and is used to control hydraulic torque converter, shift indicator light, EVAP fuel evaporation system, exhaust gas recirculation and air conditioning. When the throttle is closed, the signal voltage of the throttle position sensor is 0.2-0.7V, and when the throttle is fully open, it is 4.0V.. When PCM detects that the signal voltage of the throttle position sensor is beyond the normal range, fault codes P0 12 1 (poor performance of the throttle position sensor), P0 122 (low line voltage of the throttle position sensor), P0 1263 (high line voltage of the throttle position sensor) and P/kloc-will be set.