Fendt A002 – EST Comfort Module: Communication Fault in the System

A control module has detected a loss or corruption of data being transmitted on the Controller Area Network (CAN bus). The CAN bus is a two-wire network that allows various electronic control units (ECUs) throughout the tractor to exchange information. This generic communication error can be triggered by a variety of underlying issues and often results in the loss of specific functions, such as automatic cruise control.

• Farmer 400 Series
• Favorit 700 Series
• Favorit 900 Series
• 700 Vario Series
• 711
• 712
• 714
• 716
• 800 Vario Series
• 815
• 817
• 818
• 900 Vario Series
• 711 Vario
• 712 Vario
• 714 Vario
• 400 COM3 series

1. 1

   Retrieve all active and stored fault codes from the tractor's display to get a complete picture of the issue

2. 2

   Inspect all fuses in the main and secondary fuse boxes, specifically those supplying power to the transmission control unit, engine control unit, and comfort modules

3. 3

   Visually inspect the wiring harnesses connected to the Comfort Module (E-Box) and the EDC for chafing, corrosion on connectors, pinched wires, or loose connections

4. 4

   Measure CAN Bus resistance with the ignition off and network asleep: resistance across CAN High and CAN Low should be approximately 60 Ohms (120 Ohms indicates an open circuit or terminating resistor issue)

5. 5

   Check CAN voltage levels with the ignition on: CAN High should be 2.5-3.0 volts, and CAN Low should be 2.0-2.5 volts

6. 6

   Check for shorts to ground: measure resistance from CAN High and CAN Low lines to chassis ground (should read megaohms/open circuit; low resistance indicates a short)

1. 1

   Rectify simple faults

   Replace any blown fuses and repair any visible damage to the wiring harness found during the initial inspection. Clear the fault codes and operate the tractor to see if the A002 code returns.

2. 2

   Isolate the fault

   If the fault persists, use the tractor's specific electrical schematic to identify the connectors for the Transmission-BUS and Comfort-BUS.

3. 3

   Test wiring segments

   Disconnect the relevant modules and test the continuity and integrity of the CAN bus wires between the EST Comfort Module and the EDC module. Repair or replace any faulty sections of the harness.

4. 4

   Module diagnosis

   If the wiring is confirmed to be in good condition, the fault may be internal to either the EST Comfort Module or the EDC. Use specialized diagnostic tools to isolate the malfunctioning unit. The module may need to be sent to a specialist for testing and repair.

5. 5

   Replacement and reprogramming

   If a control module is found to be faulty, replace it. A new module requires EOL (End-of-Line) programming or calibration by a certified Fendt technician to function correctly with the tractor's specific configuration.