CLAAS 7F01h – DBD: Communication Error Between SFA and DBD

A communication error has occurred between the Suspended Front Axle (SFA) module and the Dashboard (DBD) module. This fault is triggered when the dashboard does not receive a message from the SFA module via the CAN bus network for more than 5 seconds, indicating an interruption in the data exchange between these two electronic control units. The system is designed to return to normal operation once communication is re-established.

• Axion 810
• Axion 850
• Axion 960
• Axion 800 Series
• Axion 900 Series

1. 1

   Visually inspect the connectors and the continuity of the wiring harnesses connecting the SFA module (A102) and the DBD module (A101) for signs of corrosion, damage, or loose connections

2. 2

   Verify that both the SFA and DBD modules are receiving the correct voltage and have a solid ground connection, including checking relevant fuses

3. 3

   Test CAN bus termination resistors with the power off by measuring resistance across the CAN High and CAN Low lines (a healthy network should read approximately 60 Ohms; 120 Ohms suggests a missing resistor, while lower indicates a short or extra resistor)

4. 4

   Measure CAN bus voltage levels with the power on and the bus idle (CAN High should be 2.5V to 3.0V, and CAN Low should be 2.0V to 2.5V)

5. 5

   Isolate the fault by disconnecting modules from the network one at a time to see if communication is restored

6. 6

   Connect the tractor to the CLAAS Diagnostic System (CDS) to directly communicate with individual modules and pinpoint the source of the communication breakdown

1. 1

   Address preliminary findings

   Based on the diagnostic checks, repair any identified issues with the wiring harnesses, connectors, power supply, or CAN bus termination.

2. 2

   Clear fault codes

   After performing any repairs, clear all error codes from the system memory.

3. 3

   Test operation

   Operate the tractor to verify if the communication fault code reappears.

4. 4

   Replace faulty module

   If the diagnostic checks point to a faulty module (either the SFA or DBD) and all wiring/CAN bus causes have been ruled out, replace the affected module.

5. 5

   Program and calibrate

   Use the CLAAS Diagnostic System (CDS) to program and calibrate the newly installed module to ensure it functions correctly with the specific tractor configuration.