Fendt 06.1.57 – A039 - MFA (Multifunction Armrest): PTO Speed Preselection Button Pressed Continuously

The system has detected that the PTO Speed Preselection Button (750 rpm or 540E rpm) has been pressed continuously for more than 30 seconds. The tractor's logic flags this as either a mechanical fault (jammed or stuck button) or an electrical fault (short circuit). As a result, the tractor disables the PTO speed preselection function to prevent unintended operation.

• 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 300 Vario series
• Fendt 400 Vario series
• Fendt 700 Vario series
• Fendt 800 Vario series
• Fendt 900 Vario series (916, 922, 924, 927, 930, 933, 936)

1. 1

   Examine the PTO speed preselection button on the armrest to check if it feels physically stuck, lacks its normal tactile 'click,' or is jammed by dirt, spilled liquids, or debris.

2. 2

   Use the tractor's onboard terminal or the FENDIAS diagnostic software to monitor the live state of the A039 MFA inputs and verify if the system is actively reading the button as 'Pressed/Active'.

3. 3

   Using a 160-pin adapter box, test the specific pins for the PTO button for continuity to determine if the switch is internally shorted.

4. 4

   Inspect the wiring harness connecting the button sub-panel to the main MFA circuit board for pinched wires or short circuits.

1. 1

   Power Down

   Turn off the tractor ignition and disconnect the battery to prevent electrical damage while working on the armrest.

2. 2

   Disassemble the Armrest

   Remove the retaining screws on the underside or perimeter of the A039 Multifunction Armrest to lift the upper housing and access the internal switch panels.

3. 3

   Clean the Switch

   If the button is physically sticking due to debris or dried liquids, use an electrical contact cleaner and a soft brush to clean the housing around the button. Actuate it several times to free it up.

4. 4

   Replace the Switch/Module

   If cleaning does not resolve the mechanical stick, or if the button is internally shorted, the switch must be replaced. Depending on the armrest version, you may need to replace the specific membrane keypad or the PTO switch sub-module.

5. 5

   Reassembly

   Reconnect all internal ribbon cables and wiring harnesses. Secure the armrest housing back together.

6. 6

   Clear Codes

   Reconnect the battery, turn on the ignition, and use the terminal or FENDIAS tool to clear the stored 06.1.57 fault code.

7. 7

   Functional Test

   Press the 750/540E PTO speed button normally to ensure the speed preselects correctly and the fault code does not return.