Fendt A.1.D5 – Basic Control Unit (ECU A050) / Auxiliary Control Units module: S022 - "Lower" external pushbutton — No valve operation available

This fault code indicates a signal fault or key fault with the S022 external "Lower" button for the front power lift. The system has detected that the button is faulty, experiencing a signal error, or suffering from "double actuation" (mechanically stuck). As a result, the front power lift cannot be lowered properly, and the system forces the associated spool valve into a neutral/locked position until the next trouble-free cold start.

• 409 Vario
• 410 Vario
• 411 Vario
• 412 Vario
• 711 Vario
• 712 Vario
• 714 Vario
• 715 Vario
• 716 Vario
• 717 Vario
• 718 Vario
• 916 Vario
• 920 Vario
• 924 Vario
• 926 Vario
• 930 Vario
• 411 Vario COM III
• 412 Vario COM III
• 413 Vario COM III
• 414 Vario COM III
• 415 Vario COM III
• 712 Vario COM III
• 714 Vario COM III
• 716 Vario COM III
• 718 Vario COM III
• 818 Vario COM III
• 820 Vario COM III
• Farmer 400 Vario
• Favorit 700 Vario
• Favorit 900 Vario
• 300 Vario
• 400 Vario
• 700 Vario
• 800 Vario
• 900 Vario
• 713 Vario
• 815 Vario
• 816 Vario
• 817 Vario
• 818 Vario
• 819 Vario
• 820 Vario
• 933 Vario
• 936 Vario
• 939 Vario

1. 1

   Inspect the S022 external Lower pushbutton for physical jamming, dirt, debris, or freezing causing a stuck signal.

2. 2

   Disconnect the switch and test for electrical continuity to verify it opens and closes correctly.

3. 3

   Inspect the wiring harness leading to the S022 switch for chafing, breaks, or corrosion at the connector.

4. 4

   Perform a cold start (completely power down and restart) after clearing debris to see if the fault resets.

1. 1

   Secure the Machine

   Park the tractor on level ground. Ensure the front power lift is fully lowered to the ground or mechanically supported to relieve all hydraulic pressure. Turn off the engine and remove the key.

2. 2

   Locate the Switch

   Locate the S022 "Lower" switch on the external front power lift control panel (front left).

3. 3

   Remove the Faulty Switch

   Disconnect the electrical harness connector from the back of the switch. Depress the retaining clips or remove the mounting screws to extract the S022 switch from the housing.

4. 4

   Clean the Area

   Clean the connector plug with electrical contact cleaner and clear any dirt from the switch housing bracket.

5. 5

   Install the New Part

   Snap or screw the new OEM pushbutton switch into the housing. Reconnect the electrical harness, ensuring the weather seal is intact.

6. 6

   System Reset

   Turn the tractor's battery power back on and start the engine to initiate a trouble-free cold start. This will clear the ECU lockout.

7. 7

   Test Operation

   Test the external "Raise" (S021) and "Lower" (S022) buttons to confirm the front power lift operates smoothly and the fault code does not return.