I Need Help With Multi Material Printing

[spegelius]

Ok had a look at configuration_adv.h and it seems that by default Marlin doesn have the sensor functionality enabled:

   //#define PRUSA_MMU2_S_MODE
  #if ENABLED(PRUSA_MMU2_S_MODE)
    #define MMU2_C0_RETRY   5             // Number of retries (total time = timeout*retries)

    #define MMU2_CAN_LOAD_FEEDRATE 800    // (mm/min)
    #define MMU2_CAN_LOAD_SEQUENCE \
      {  0.1, MMU2_CAN_LOAD_FEEDRATE }, \
      {  60.0, MMU2_CAN_LOAD_FEEDRATE }, \
      { -52.0, MMU2_CAN_LOAD_FEEDRATE }

    #define MMU2_CAN_LOAD_RETRACT   6.0   // (mm) Keep under the distance between Load Sequence values
    #define MMU2_CAN_LOAD_DEVIATION 0.8   // (mm) Acceptable deviation

    #define MMU2_CAN_LOAD_INCREMENT 0.2   // (mm) To reuse within MMU2 module
    #define MMU2_CAN_LOAD_INCREMENT_SEQUENCE \
      { -MMU2_CAN_LOAD_INCREMENT, MMU2_CAN_LOAD_FEEDRATE }

  #endif

So it's something else. Have you enabled #define MMU2_MENUS?