Fendt B.1.12 – A002 / A008: Electrical fault in TI automatic operation

Variotronic TI (Tractor Management System / Teach-In) automatic function is disabled, meaning the Teach-in does not function.

• 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) / Farmer 400 (409, 410, 411, 412, 413, 414, 415)
• Fendt 700 Vario (COM III) / Favorit 700 (711, 712, 714, 716, 718)
• Fendt 800 Vario (COM III) (815, 817, 818, 820)
• Fendt 900 Vario (COM III) / Favorit 900 (916, 920, 924, 926, 930)

1. 1

   Check Terminal Settings: Verify that the Variotronic TI settings in the A008 Vario Terminal are configured correctly.

2. 2

   CAN Bus Communication Check: Verify that the passive bus system ends are properly sealed off with terminating resistors.

3. 3

   Power Supply & Fuses: Check the power supply for the CAN bus on circuit board A013, specifically inspecting fuses F039, F040, F041, and F046.

4. 4

   Diagnostic Menu Verification: Turn the ignition ON, press F5 to navigate to the main menu levels on the A008 terminal, and open Diagnostics Menu 1 to monitor the ECU load and sensor feedback.

1. 1

   Inspect Wiring Harness

   Access the wiring harness connecting the A008 Vario Terminal to the A002 Enhanced Control ECU (E-Box). Look for chafed wires, loose connector pins, or corrosion, particularly at the ECU connectors (e.g., X031).

2. 2

   Test Voltage and Ground

   Measure the signal voltage at the A002 ECU (pin 1 and pin 2). The E-box generates a basic signal voltage that is reduced by resistances to earth. Ensure the ECU is receiving proper 12 VDC supply voltage.

3. 3

   Replace Fuses/Relays

   If any of the CAN bus power supply fuses on the A013 circuit board (F039, F040, F041, F046) are blown, replace them and retest the Teach-in function.

4. 4

   Software/EOL Reprogramming

   If the wiring and power supply are intact, the A002 ECU may have a programming error or EEPROM checksum fault. In this case, End-of-Line (EOL) reprogramming or flashing a new data record via FENDIAS is required.

5. 5

   Component Replacement

   If the A002 ECU or A008 Terminal has suffered an internal hardware failure and cannot be flashed, the faulty module must be replaced and calibrated to the tractor.