CLAAS Id7706h / 7706h – BDG (A103) module: Transmission module TR2 (A57-2) has detected communication loss with the external function module EXT (A62) during a CSM sequence

The tractor's CAN bus network has lost communication between the transmission control module (TR2) and the external functions module (EXT) while executing a CLAAS Sequence Management (CSM) operation (headland management). The CSM sequence is immediately stopped. The system will wait for the sequence to be relaunched.

• CLAAS Axion 800 Series
• CLAAS Axion 810
• CLAAS Axion 850
• CLAAS Arion 600 / 500 Series
• CLAAS Arion 510
• CLAAS Arion 610
• CLAAS Arion 630
• CLAAS Arion 640
• CLAAS Arion 400 Series
• CLAAS Arion 410
• CLAAS Arion 430

1. 1

   Check the TR2 transmission module (A57-2): Verify the physical condition of the module (located behind the driver's seat on many models) and its 42-terminal connector.

2. 2

   Check the external function module EXT (A62): Inspect the wiring harness and connector for corrosion, backed-out pins, or moisture.

3. 3

   Check the CLAAS Vehicle CAN Bus Network: Test the CAN bus lines between the A57-2, A62, and A103 modules for short-circuits to ground, short-circuits to 12V, or open circuits.

4. 4

   Check Power and Ground: Verify the sources of energy (fuses, power supply, and ground) for both the TR2 and EXT modules.

1. 1

   Reset the Sequence

   Because the system response halts the operation, first try to clear the error by waiting for the sequence to relaunch or manually resetting the CSM via the Cebis terminal.

2. 2

   Inspect Wiring & Connectors

   Disconnect the batteries. Locate the TR2 (A57-2) module and EXT (A62) module. Disconnect their harnesses and clean the contacts with electrical contact cleaner. Reconnect and ensure the locking mechanisms are fully seated.

3. 3

   Test CAN Bus Integrity

   Using a multimeter, measure the CAN resistor values and check for continuity on the CAN High and CAN Low lines between the A57-2 module, the A62 module, and the A103 Gateway. Repair any broken wires or chafed harnesses.

4. 4

   Module Testing via CDS

   Connect the CLAAS Diagnostic System (CDS) laptop. Check if the EXT (A62) or TR2 (A57-2) modules are dropping off the network entirely or if the communication loss is isolated to the CSM sequence.

5. 5

   Replace Faulty Module

   If wiring is intact but communication cannot be established, the faulty module must be replaced. (Note: The TR2 module is an "Auto 5" type generic electronic module).

6. 6

   Reprogramming

   If the TR2 (A57-2) module is replaced, it must be configured and calibrated using the CLAAS Diagnostic System (CDS) or CLAAS special tool no. 60 05 033 249.