Fendt S022 – A050: External Button 'Lower' Malfunction

The system has detected an abnormal signal from the external pushbutton used for lowering the front power lift. This can be caused by the button being physically stuck, a double actuation signal, or an electrical fault in the circuit. As a safety measure, the external lowering function becomes inoperable and the associated hydraulic valve is commanded to its neutral position.

• 200 Vario
• 300 Vario
• 400 Vario
• 500 Vario
• 700 Vario
• 800 Vario
• 900 Vario
• Farmer
• Favorit

1. 1

   Visually inspect the external 'lower' button for obvious damage or signs of being physically stuck or jammed.

2. 2

   Disconnect the electrical connector at the switch and check for a proper earth connection.

3. 3

   Inspect the signal wiring at the switch for breaks or short circuits (such as an earth connection in the signal wire).

4. 4

   Measure switch resistance with it disconnected: an open switch should show infinite resistance, while a closed (pressed) switch should show approximately 0 ohms.

5. 5

   Check signal voltage at the switch connector: expected voltage when open is around 6.1V DC (from A050) or 8.0V DC (from A002), dropping to 0V DC when closed.

6. 6

   Test the wiring harness between the switch and the control unit using a breakout box or adapter at the E-box (ECU) to check for breaks or short circuits.

7. 7

   Isolate the ECU by opening the bridge on the adapter box to measure directly to the E-box, confirming if the ECU itself is faulty.

1. 1

   Confirm fault location

   Use the diagnostic checks to isolate the fault to either the switch itself, the wiring harness, or the ECU.

2. 2

   Replace the switch

   If the switch is determined to be faulty or physically stuck, replace it. The external mounting generally makes it easily accessible.

3. 3

   Repair wiring and clean connections

   If the wiring harness is damaged, repair or replace the affected section. Thoroughly clean all electrical connections to remove corrosion and apply dielectric grease during reassembly.

4. 4

   Clear fault codes

   After the repair is complete, clear the stored fault codes from the system memory.

5. 5

   Test operation

   Start the tractor and test the functionality of the external front power lift 'lower' button to ensure the repair was successful.