Fendt B.1.42 – A002 ECU / A008 Vario Terminal: Communications error / error counter overflow

Data transfer between the Vario Terminal and the enhanced control unit regarding the automated headland management system (Teach-in) has failed or timed out, preventing Variotronic TI automated functions from operating.

• 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 Farmer 400 Vario
• Fendt Favorit 700 Vario
• Fendt Favorit 900 Vario
• Fendt 300 Vario
• Fendt 400 Vario
• Fendt 700 Vario
• Fendt 800 Vario
• Fendt 900 Vario
• Fendt 300 Vario COM III
• Fendt 400 Vario COM III
• Fendt 700 Vario COM III
• Fendt 800 Vario COM III
• Fendt 900 Vario COM III

1. 1

   Restart the tractor to see if the memory/communication error clears itself

2. 2

   Check the CAN bus power supply located in circuit board A013 and inspect related fuses (F039, F040, F041, or F046)

3. 3

   Inspect the wiring harness and connectors between the A008 Vario Terminal and the A002 E-box for loose connections, corrosion, or broken wires

4. 4

   Connect the FENDIAS diagnostic tool to check for dropped programming or software corruption in the A002 ECU

1. 1

   Cycle Power

   Turn the tractor off, wait for the ECUs to power down completely, and restart. If the code B.1.42 changes to an inactive state, clear the code and test the Teach-in function.

2. 2

   Inspect Physical Connections

   If the code remains active, access the rear of the A008 Vario Terminal and the A002 E-box. Disconnect the harnesses, clean the pins with electrical contact cleaner, and ensure they are seated securely.

3. 3

   Test CAN Bus Continuity

   Using a multimeter, verify the continuity and resistance of the CAN bus lines between the terminal and the E-box. Repair any damaged wiring.

4. 4

   Software Reprogramming (EOL)

   If the wiring is intact, the issue is likely a software glitch in the A002 E-box. A dealer technician must use the FENDIAS tool to perform an End-Of-Line (EOL) reprogramming or flash a new data record to the ECU.

5. 5

   Module Replacement

   If EOL programming fails or the module will not communicate at all, the faulty component (either the A008 Vario Terminal or the A002 E-box) must be replaced and calibrated to the tractor.