Fendt F.1.00 – A002 ECU / A050 ECU: A034 - Driving switch, CAN bus

Loss of CAN bus communication with the A034 Driving Switch (multifunction joystick), or an internal electrical fault within the joystick itself (such as a failure of the accelerator pedal release potentiometer or hand throttle memory buttons). The tractor typically enters a restricted operating mode (emergency operation), and auxiliary control valves or throttle pedal modes may become inoperable.

• 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 Farmer 400 Vario
• Fendt Favorit 700 and 900 Vario
• Fendt 300, 400, 700, 800, and 900 Vario (including COM III generations)
• Fendt Squadra 1290 UD

1. 1

   Verify the power supply for the CAN bus located on circuit board A013

2. 2

   Inspect fuse F047 (Joystick CAN), as well as fuses F040, F041, and fuse 13 (8.5 V supply)

3. 3

   Inspect the CAN connection wiring between the A002 ECU (enhanced control) and the A034 Drive switch for breaks, corrosion, or loose pins

4. 4

   Use the Variotronic TI terminal (Diagnostics Menu 1) to check the 'IDEAL' target value for the transmission ratio coming from the A034 joystick to see if any signal is being registered

1. 1

   Power & Fuse Verification

   Start by replacing any blown fuses on circuit board A013 (specifically F047). If the fuse blows again, trace the harness for a short to ground.

2. 2

   Harness Repair

   If the fuses are intact, test the continuity of the CAN bus wiring between the A034 joystick and the A002 ECU. Repair any damaged wiring.

3. 3

   Component Replacement

   If the wiring and power supply are verified as good, the internal potentiometers or memory buttons of the A034 joystick are likely defective (e.g., 'slide switch' failure). The A034 Driving Switch must be replaced.

4. 4

   Calibration / Teach-in

   After replacing the A034 joystick, you must calibrate the new component. Run the EOL (End of Line) programming or use calibration code 4010 to calibrate the accelerator pedal release potentiometer ('slide switch') on the new joystick.

5. 5

   Clear Codes

   Clear the fault codes using FENDIAS or the tractor's terminal and test drive to ensure emergency mode is lifted and auxiliary functions are restored.