CLAAS Id781Bh / 781Bh – HYD (A60): Front Lifting Position Sensor Signal Short-Circuited at Ground

The voltage of the signal from the front lifting position sensor is short-circuited at ground, causing the front lifting mechanism to operate without position checks.

• Axion 800
• Axion 810
• Axion 830
• Axion 840
• Axion 850
• Axion 920
• Axion 950
• Axion 960
• Arion 530
• Arion 550
• Arion 620
• Arion 650
• Xerion 3300
• Xerion 3800

1. 1

   Inspect the front lifting position sensor (B139-1).

2. 2

   Verify the condition of the hydraulic module HYD (A60).

3. 3

   Check the connectors and the continuity of the wiring harnesses linking the B139-1 sensor to the A60 module.

4. 4

   Test the supply harness for a short-circuit to ground or an open circuit, as harness damage is a common trigger for this specific code.

1. 1

   Disconnect battery

   Before working on the electrical or hydraulic systems, always disconnect the battery negative (–) cable.

2. 2

   Locate sensor

   Locate the front lifting position sensor (B139-1) on the front linkage assembly.

3. 3

   Remove faulty sensor

   If wiring tests confirm the harness is intact but the sensor is internally shorted to ground, remove the faulty sensor.

4. 4

   Install and adjust new sensor

   Install the new sensor, observing physical adjustment dimensions (e.g., on Xerion 3300/3800 models, the adjustment dimension is 140+1 mm for a standard front linkage, or 70+1 mm for a pivoting linkage).

5. 5

   Calibrate sensor

   After replacement, calibrate the front lifting position sensor using the CLAAS Diagnostic System (CDS) so the calibration values are relearned by the HYD module.