CLAAS Id77B8h / 77B8h (13) – HYD (A60) - Hydraulic Module: Instruction message from valve 2 is not in the right format

The system receives an invalid or improperly formatted instruction signal from valve 2, triggering the safety protocol and causing electrodistributor 2 (spool valve 2) to automatically return to neutral.

• Axion 800 series
• Axion 810
• Axion 820
• Axion 830
• Axion 840
• Axion 850

1. 1

   Verify the Hydraulic CAN bus network is communicating properly without excessive frame errors

2. 2

   Check the electrodistributor module (A105-2) controlling valve 2

3. 3

   Ensure the main hydraulic module HYD (A60) is functioning and outputting the correct signals

4. 4

   Inspect connectors and continuity of the harnesses linking the HYD (A60) module to the A105-2 electrodistributor

5. 5

   Check for any short-circuits or open circuits in the wiring

6. 6

   Check power sources, including fuses, power supply voltage, and ground connections to the modules

1. 1

   Verify the Code and Symptom

   Confirm that code Id77B8h is active and that spool valve 2 is defaulting to the neutral position.

2. 2

   Inspect Wiring and Connectors

   Disconnect the harnesses at the HYD (A60) module and the electrodistributor module (A105-2). Inspect the pins for corrosion, moisture, or damage. Clean with contact cleaner if necessary.

3. 3

   Test Harness Continuity

   Using a multimeter, test the CAN bus lines and power/ground wires between the hydraulic module and valve 2 for continuity and ensure there are no shorts to ground or power.

4. 4

   Check Component Resistance

   If the wiring is intact, check the internal resistance of the electrodistributor module (A105-2) according to OEM specifications to see if the solenoid/module has failed internally.

5. 5

   Replace Faulty Component

   If the CAN bus network and wiring are verified as fully functional, the fault lies within the hardware. Replace the electrodistributor module (A105-2). If the issue persists, the HYD (A60) module itself may be failing to process the CAN messages correctly.

6. 6

   Clear Codes and Test

   Clear all error codes from the system using the diagnostic terminal. Operate the tractor and actuate valve 2 to ensure the anomaly does not reappear.