Fendt 5.1.64 – A004 / A002: A004 - "Suspension ON" key — Fault in signal from key to A004.

The system has detected an invalid or missing electrical signal from the "Suspension ON" button/key to the control console module. In tractors with a single e-box version, this code can also indicate a CAN bus signal failure between the A004 module and the A002 module. The front axle suspension becomes non-operational.

• 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 series
• Fendt Favorit 700 Vario series
• Fendt Favorit 900 Vario series
• Fendt 300 Vario COM III series

1. 1

   Inspect the 'Suspension ON' key on the control console for physical damage, sticking, or liquid intrusion.

2. 2

   Using a multimeter or the FENDIAS diagnostic tool, verify if the A004 module registers a state change when the 'Suspension ON' key is pressed.

3. 3

   Check the local wiring harness connecting the physical switch to the A004 control panel board for open circuits, shorts to ground, or loose connector pins.

4. 4

   If the switch tests fine, consult the 'CAN/enhanced controls bus' circuit diagram and test the CAN bus communication lines between the A004 Control Panel and the A002 Enhanced Control ECU for continuity and proper termination resistance.

1. 1

   Power Down

   Turn off the tractor and disconnect the battery ground to prevent electrical shorts during disassembly.

2. 2

   Access the Console

   Carefully remove the trim panels on the right-hand control console/armrest to access the A004 module and the suspension switch block.

3. 3

   Inspect and Clean

   Disconnect the harness from the "Suspension ON" switch. Inspect the pins for corrosion or bent terminals. Clean with contact cleaner if necessary.

4. 4

   Test/Replace the Switch

   Test the switch for continuity when pressed. If the switch fails to close the circuit or is internally shorted, replace the switch assembly.

5. 5

   Repair Bus Wiring (If Applicable)

   If the switch is functional, trace the CAN bus harness from the A004 module to the A002 ECU. Repair any chafed wires or replace damaged connector housings.

6. 6

   Reassembly and Clearing

   Reconnect all harnesses, restore battery power, and turn the ignition on. Use the FENDIAS system or the tractor's onboard terminal to clear the inactive 5.1.64 fault code.

7. 7

   Operational Test

   Start the tractor, drive at a low speed, and press the "Suspension ON" key to verify that the front axle suspension engages and levels correctly.