Fendt 4.1.70 – A004 - ECU, Control Panel: A004 - 'Cruise control 1' key

This fault code indicates a key failure or signal fault originating from the 'Cruise Control 1' button, meaning the system is detecting a faulty button press (e.g., a stuck or damaged key) or there is a CAN bus communication failure between the A004 control panel and the transmission control module. As a result, Cruise control 1 cannot be activated.

• 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
• Farmer 400 Vario
• Favorit 700 Vario
• Favorit 900 Vario
• 300 Vario Series
• 400 Vario Series
• 700 Vario Series
• 800 Vario Series
• 900 Vario Series

1. 1

   Inspect the 'Cruise Control 1' button on the A004 membrane keypad for physical damage, sticking, or heavy wear.

2. 2

   Check the power supply to the A004 control console by inspecting fuses F040 and F041 on the A013 fuse board.

3. 3

   Test the CAN bus connection between the A004 Control Panel and the A002 EST (Transmission Control Module) for continuity issues, short circuits to ground, or corroded pins at connectors X031 and X033.

1. 1

   Power Down

   Turn off the tractor ignition and disconnect the battery master switch to prevent electrical shorts.

2. 2

   Resolve Power/Wiring Issues

   If the diagnostic checks revealed blown fuses on the A013 board or damaged wiring between the A004 and A002 modules, replace the fuses or repair the wiring harness. Re-test the system.

3. 3

   Address the Keypad

   If the wiring is intact but the button is physically damaged or unresponsive, the membrane keypad is likely the culprit.

4. 4

   Membrane Replacement

   If the internal board of the A004 is fine but the membrane is worn, carefully peel off the old protective adhesive film/membrane and install a replacement comfort module sticker. Ensure it is attached firmly and straight.

5. 5

   Module Replacement

   If the button failure is internal to the A004 ECU circuit board, the entire A004 Control Console must be replaced.

6. 6

   Finalize

   Reconnect the battery, turn on the ignition, clear the stored fault codes via the terminal, and test the Cruise Control 1 function.