CLAAS Id78BAh / 78BAh (850) – TR3 (A57-3) Transmission Module: Rear power take-off disconnected during a sequence CSM.

This code indicates that the rear Power Take-Off (PTO) was unexpectedly disconnected or failed to operate correctly while an automated CLAAS Sequence Management (CSM - headland management) sequence was actively running. The immediate consequence is that the rear PTO becomes inoperative.

• Axion 810
• Axion 820
• Axion 830
• Axion 840
• Axion 850
• Axion 920
• Axion 930
• Axion 940
• Axion 950
• Arion 410
• Arion 430
• Arion 510
• Arion 640

1. 1

   Wait for Auto-Initialization: Observe if the tractor recovers on its own after 20 seconds and attempts to relaunch the sequence.

2. 2

   Check for Accompanying Codes: Look for code Id78BBh (851), which indicates the TR3 (A57-3) module lost communication with the EXT (A62) external function module.

3. 3

   Inspect the CSM Switch: Verify the physical condition and signal of the CLAAS Sequence Management switch (Component S177).

4. 4

   Harness and Connector Check: Check connectors, wiring continuity, and power/ground sources for the TR3 module (behind the driver's seat) and the EXT module.

1. 1

   Manual CSM Reset

   If the tractor does not auto-initialize after 20 seconds, you must manually reset the CSM. Switch the CSM switch (S177) to the 'play' position before selecting a sequence, or pause and restart the sequence using the CEBIS terminal display.

2. 2

   Hard Reset (Park-Lock / Standby clear)

   If the module is stuck in standby or the sequence will not clear, turn off the tractor's main battery switch, wait for at least 30 seconds, and restart the engine.

3. 3

   ISC Reverser Reset

   In some instances, the reverser requires a reset to clear transmission module lockouts. With the engine running, fully depress the clutch pedal.

4. 4

   Clear Codes

   Clear all error codes from the CEBIS terminal or via the CLAAS Diagnostic System, then test drive the tractor and run a CSM sequence to see if the anomaly returns.

5. 5

   Component Replacement

   If the fault persists and wiring tests confirm no open/short circuits, the TR3 module or the EXT module may require replacement and reprogramming/calibration.