Defect code memory

The defect detection facility for the MFL control unit detects following defects and stores them as defect codes in the defect code memory:

• Data interruption: A defect code is stored in the defect code memory if an interruption occurs in the data link between the MFL operating unit and MFL control unit.
  
• Buttons on right: If the MFL control unit detects that both buttons of the right-hand rocker switch are depressed, this indicates a defect in the button unit and a corresponding defect code is stored in the defect code memory.
  
• Buttons on left: If the MFL control unit detects that both buttons of the left-hand rocker switch are depressed, this indicates a defect in the button unit and a corresponding defect code is stored in the defect code memory.
  
• Short circuit in steering wheel supply voltage: An impermissibly high current flows through the MFL steering wheel if the difference between the supply voltage of the MLF control unit and the supply voltage of the MFL operating unit is more than 3 V.
  
• EEPROM write error: A defect code is stored if a fault occurs when writing data in the non-volatile memory in the MFL control unit.