The thermistor for the MPP motors at low temperatures is around 100ohm resistance for all motors except the P high voltage winding motors which less than 300ohm.
At 145C internal temperature, the thermistor increases in resistance abruptly to 1kohm to 3kohm.
Even though the motor windings are rated at 125C that is near the top end of where normal operation would be expected. The windings can actually handle up to 180C internal so there is adequate time to prevent damaging the motor.
Thermistor resistance vs temperature curve