CLAAS Id75DAh / 75DAh (327) – TR1 (A57-1) Transmission Control Module 1: Physical error on the CAN network. At least one of the tractor computers is not detected or CAN network overload.

The Powertrain CAN bus is experiencing a physical layer failure (such as a short circuit, open circuit, or faulty terminating resistor) or a specific module is flooding the network with corrupted data frames, causing a communication blackout where expected modules drop offline.

• Arion 410
• Arion 430
• Arion 510
• Arion 530
• Arion 550
• Arion 610
• Arion 620
• Arion 630
• Arion 640
• Arion 650
• Axion 800
• Axion 810
• Axion 850
• Axion 960
• Ares 657 ATZ

1. 1

   Use the CLAAS Diagnostic System (CDS) to ping all modules on the Powertrain CAN bus to see which ones are offline.

2. 2

   Verify the CAN network communication module (BDG) is transmitting messages. Check for accompanying codes like Id7701h or Id7702h.

3. 3

   Locate and test the CAN bus shunts (terminating resistors) behind the instrument panel, behind the seat, or under the left-hand console.

4. 4

   Verify power and ground supplies to the 28-pin and 32-pin connectors on the TR1 (A57-1) module.

1. 1

   Isolate the Network

   Disconnect the battery. Using a multimeter, measure the resistance across CAN High and CAN Low at the diagnostic port or TR1 connector. A healthy CAN bus should read approximately 60 ohms. If it reads 120 ohms, a terminating resistor (shunt) is broken or disconnected. If it reads near 0 ohms, the CAN lines are shorted together.

2. 2

   Inspect Wiring and Shunts

   Physically inspect the Powertrain CAN bus wiring harness for chafing, particularly where it routes near the transmission housing and cab mounts. Test the shunts located under the left-hand console or behind the instrument panel. Replace any damaged wiring or faulty shunts.

3. 3

   Module Drop-Testing

   If the wiring and resistance are good but the network is overloaded (shorted to power/ground internally by a module), disconnect modules on the Powertrain CAN bus one by one (starting with the BDG A103 and TR1 A57-1). Check the network status after each disconnection. The module that restores network communication when unplugged is the internally shorted culprit.

4. 4

   Replace Faulty Module

   If the TR1 (A57-1) or BDG (A103) is found to be pulling the network down, replace the module.

5. 5

   Reset and Calibrate

   Reconnect the battery. Connect the CLAAS Diagnostic System (CDS). Clear the inactive fault codes and perform the requested "ISC" reset (Interactive System Control reset) while the tractor is stopped.