Fendt 0A.1.D6 – Hydraulics / Enhanced Control ECU (A002 or A005): S021 - Switch (external), raise front power lift

The system has detected a "Signal fault" or a "Faulty button". This often means the button is stuck, experiencing double actuation, or has an electrical short/open circuit. The external raise button is rendered inoperable by the system as a safety precaution until the next trouble-free cold start.

• 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 (e.g., 307, 308, 309, 310, 311, 312)
• Fendt 400 Vario / Farmer 400 (e.g., 409, 410, 411, 412)
• Fendt 700 Vario / Favorit 700 (e.g., 711, 712, 714, 716)
• Fendt 800 Vario / Favorit 800 (e.g., 815, 816, 817, 818, 822, 824)
• Fendt 900 Vario / Favorit 900 (e.g., 916, 920, 924, 926, 927, 930, 933, 936)

1. 1

   Inspect the S021 external raise button for physical jamming, sticking, or damage caused by debris or moisture.

2. 2

   Perform a cold start reset by turning the tractor off completely and restarting to see if the fault clears.

3. 3

   Test the signal voltage at the switch with the ignition ON using a multimeter (should read ~3.7 VDC when not actuated, and drop to ~1.8 VDC when pressed).

4. 4

   Inspect the 3-pin connector and the wiring harness leading back to the ECU for continuity, corrosion, or shorts to ground.

1. 1

   Power Down

   Turn off the tractor ignition and disconnect the battery to prevent electrical shorts.

2. 2

   Locate the Switch

   Locate the S021 external raise push button on the front power lift assembly.

3. 3

   Disconnect

   Unplug the 3-pin electrical connector from the back of the switch.

4. 4

   Remove

   Unclip or unscrew the faulty switch from its mounting bracket on the tractor chassis.

5. 5

   Install

   Insert the new OEM replacement switch into the mounting bracket and ensure it is secure.

6. 6

   Reconnect

   Plug the 3-pin electrical connector into the new switch.

7. 7

   Test

   Reconnect the battery, turn the ignition on (performing a cold start), and test the external raise function to ensure the 0A.1.D6 code has cleared and the lift operates correctly.