CLAAS Id781Dh / 781Dh – HYD (A60) - Hydraulic Control Module: Signal of the front lifting position sensor high or outside calibration range.

The front lifting mechanism operates without position check (loss of position control).

• CLAAS Axion 800 Series (810, 830, 850, 870)
• CLAAS Axion 900 Series (920, 930, 940, 950, 960)
• CLAAS Arion Series (510-640)
• CLAAS Xerion Series (3300, 3800)

1. 1

   Check the connectors and continuity of the wiring harnesses linking the B139-1 sensor to the HYD A60 module for damaged pins, corrosion, or loose connections.

2. 2

   Test the circuit for any short-circuits (to ground or 12V) or open circuits.

3. 3

   Check the sources of energy (fuses, 5V/12V supply voltage, and ground) at the sensor connector.

4. 4

   Inspect the front linkage mechanism to ensure it is not mechanically seized, bent, or obstructed, which could force the sensor outside its physical calibration range.

5. 5

   Check the sensor's resistance and physical adjustment/mounting position to ensure it hasn't vibrated loose.

1. 1

   Preparation

   Note all error codes present on the tractor to analyze interactions (one code can generate another). Disconnect the battery negative (–) cable before beginning electrical repairs.

2. 2

   Inspect & Test

   Locate the front lifting position sensor (B139-1) on the front linkage assembly. Perform the electrical continuity and voltage checks.

3. 3

   Adjust or Replace

   If the wiring is intact but the signal remains out of range, adjust the sensor mounting if it has shifted. If it fails resistance testing, remove and replace the sensor.

4. 4

   Reassembly

   Reconnect the battery.

5. 5

   Calibration

   Using the CLAAS Diagnostic System (CDS), navigate to the calibration menu and perform the 'Front lifting position sensor' calibration. The system will learn the new minimum and maximum values (LearnFrontHitchPositionMin and LearnFrontHitchPositionMax).

6. 6

   Clear & Verify

   Clear all error codes from the HYD module. Test the front linkage through its full range of motion to ensure the anomaly does not reappear and position control is restored.