Fendt 04.1.33 – MFA (Multifunction Armrest) module: MFA, multifunction armrest - Faulty joystick signal 'v+' (joystick forward)

The control unit is detecting an invalid, missing, or out-of-range signal from the Vario joystick when the operator pushes it forward to accelerate or change the transmission ratio. Continuation in emergency mode is possible.

• 922 Vario COM III
• 924 Vario COM III
• 927 Vario COM III
• 930 Vario COM III
• 933 Vario COM III
• 936 Vario COM III
• Fendt 400 Vario series
• Fendt 700 Vario series (711, 712, 714, 716)
• Fendt 800 Vario series
• Fendt 900 Vario series (916, 920, 922, 924, 926, 927, 930, 933, 936, 939)

1. 1

   Test the v+ (forward) travel signal output using the tractor's diagnostic terminal to see if the signal drops out at a specific physical angle.

2. 2

   Verify the 8.5V or 12V reference supply voltage to the armrest and joystick control board.

3. 3

   Check the Vario joystick for excessive physical play or wobbling, as mechanical wear in the spring tensioner or microswitches often causes the sensor to misread the forward position.

4. 4

   Consult the TRANSMISSION, MANUAL ADJUSTMENT circuit diagram to test the wiring harness connecting the joystick to the MFA control board for continuity or shorts.

1. 1

   Access the MFA

   Remove the casing on the Multifunction Armrest to expose the Vario joystick assembly.

2. 2

   Mechanical Repair

   If the joystick is physically loose but the electronics are intact, install a mechanical spare part kit (spring tensioner) to stabilize the lever and restore proper switch contact.

3. 3

   Component Replacement

   If the internal hall sensors or microswitches for the 'v+' signal are dead, replace the specific joystick switch plate or the entire Vario joystick pilot control unit.

4. 4

   Clear Codes & Calibrate

   Use the tractor's terminal to clear the stored 04.1.33 fault code from the A050 basic control unit memory and perform any necessary joystick/transmission calibrations.