Fendt A.1.FA – Basic Control Unit (ECU A050): S067 - External valve actuation button 'raise' — Button faulty / signal line faulty.

The spool valve external pushbutton for the rear lift (located on the fender) is malfunctioning, or there is a break/short in its signal line. As a result, external valve actuation is disabled, and the rear external controls will not work until the issue is resolved and the tractor undergoes a 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
• Fendt 300 Vario (COM III)
• Fendt 400 Vario (COM III)
• Fendt 700 Vario (COM III)
• Fendt 800 Vario (COM III)
• Fendt 800 Vario S4 series
• Fendt 900 Vario (COM III)
• Fendt 900 Vario S4 series
• 916
• 920
• 924
• 926
• 927
• 930
• 933
• 936
• 939

1. 1

   Inspect the S067 external raise button on the rear fender for physical damage, sticking, or water ingress. (Note: If the button is stuck and actuating at the same time as the 'lower' button, it will trigger a related A.1.FC double-actuation code).

2. 2

   Check the wiring harness and connectors between the S067 switch and the A050 Basic Control Unit for continuity, shorts to ground, or breaks.

3. 3

   Test the switch using a multimeter by measuring the signal voltage at pin 1 and pin 2 of the switch connector. When open, resistance should be infinite and signal voltage approx 6.1 VDC (for A050) or 8.0 VDC (for A002). When closed, resistance should drop indicating a closed circuit.

1. 1

   Turn off the tractor and disconnect the battery

   to ensure safety while working on the electrical system.

2. 2

   Locate the S067 external valve actuation button

   on the left-hand rear fender (or S174/175 if diagnosing the right-hand equivalent).

3. 3

   Disconnect the wiring harness connector

   from the back of the switch.

4. 4

   Remove the retaining nut/clips holding the switch in the fender housing and pull the switch out

   If the multimeter diagnostic checks confirm the switch is internally faulty (e.g., stuck open or closed).

5. 5

   Install the new OEM replacement switch

   into the fender housing and secure it.

6. 6

   Reconnect the wiring harness

   ensuring the weather seal on the connector is intact to prevent future moisture ingress.

7. 7

   Reconnect the battery and turn the ignition on.

8. 8

   Clear the fault codes

   using the terminal or SERDIA diagnostic tool. The system requires a 'trouble-free cold start' to reset the external valve actuation lockout.

9. 9

   Test the rear external lift controls

   to verify operation.