Fendt 18.1.4A – A050 - Basic Control Unit ECU (EXT): A050 - ECU, basic control unit

Communication with the TopDock (the Auto-Guide GPS receiver/antenna ECU) has been interrupted. The system will retain the last steering command.

• 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 (COM III)
• FENDT 400 Vario (COM III)
• FENDT 700 Vario (COM III)
• FENDT 800 Vario (COM III)
• FENDT 900 Vario (COM III)

1. 1

   Check for a 'Frozen' TopDock: If the tractor was switched off while power was still applied to the antenna, it can freeze before the automatic battery cut-out engages.

2. 2

   Inspect Wiring and Connections: Check the physical connection between the Auto-Guide Terminal (A059) and the TopDock GPS ECU (A058) for broken wires, short circuits, or corroded pins in the roof compartment harness.

3. 3

   Check Power Supply: Verify that voltage is reaching the TopDock (+ECU, GPS).

4. 4

   Check for Authorization Errors: Ensure the TopDock has not lost its authorization code, which can prevent it from answering the terminal.

1. 1

   Perform a Hard Reset

   If the TopDock is frozen due to an improper shutdown sequence, perform a GPS reset. Pull the dedicated GPS fuse (e.g., F23 on newer models) or disconnect the battery to completely cut power to the TopDock and force a reboot.

2. 2

   Repair Harness

   If diagnostic testing reveals a break or short in the CAN communication lines between the A050 Basic Control Unit and the A058 TopDock, repair or replace the damaged section of the wiring harness.

3. 3

   Reprogramming

   If the ECU/GPS is not answering due to a software or authorization drop, request an Authcode from FENDT After Sales Service and reprogram the Auto-Guide System.

4. 4

   Replace the TopDock

   If the TopDock receiver has suffered an internal hardware failure and will not power on or communicate after a hard reset and wiring verification, the unit must be replaced.

5. 5

   Clear Codes

   Once communication is restored, use FENDIAS diagnostic software to clear the 18.1.4A fault code from the A050 Basic Control Unit.