CLAAS Id76ABh / 76ABh (722) – REH (A58) Module: Voltage of the signal of position sensor non valid.

The control module is receiving an out-of-range, missing, or erratic voltage signal from the rear lift position sensor (Component B139-2). As a safety measure, the rear lifting function is locked out from the cab controls. The system will default to a degraded mode, and the operator must use the external fender controls to operate the lift.

• Arion 410
• Arion 420
• Arion 430
• Arion 510
• Arion 520
• Arion 530
• Arion 540
• Arion 610
• Arion 620
• Arion 630
• Arion 640
• Axion 800
• Axion 810
• Axion 850
• Axion 920
• Axion 950
• Xerion 3300
• Xerion 3800

1. 1

   Check the tractor's display for any interacting error codes (e.g., CAN bus errors) that might be causing this code as a secondary symptom.

2. 2

   Inspect the B139-2 Rear Lift Position Sensor for mechanical seizing, physical damage, or poor adjustment.

3. 3

   Test the sensor's resistance and verify the voltage output matches the specified parameters.

4. 4

   Check the wiring harness for short-circuits to ground, short-circuits to power, or open circuits between the B139-2 sensor and the A58 REH module.

5. 5

   Verify the fuses, power supply (12V/10V regulated), and ground connections to the REH (A58) module.

6. 6

   Verify if the lifting parameters have been lost and require a software recalibration.

1. 1

   Safely Secure the Machine

   Lower the rear linkage to the ground (using external controls if necessary) and turn off the master switch/battery disconnect.

2. 2

   Locate the Components

   Find the B139-2 Position Sensor, located on the rear linkage/lift arm assembly. Find the REH (A58) Module, which is typically located under the right-hand console in the cab.

3. 3

   Inspect and Clean Connections

   Disconnect the harness at the B139-2 sensor. Clean the pins with contact cleaner and check for pushed-back pins or corrosion. Do the same at the A58 module.

4. 4

   Test the Circuit

   Using a multimeter, perform a continuity test on the signal, power, and ground wires running from the sensor to the A58 module. Repair any broken wires.

5. 5

   Replace the Sensor

   If the wiring is intact but the sensor fails resistance/voltage checks (or is mechanically seized), remove the mounting hardware and replace the B139-2 sensor. Ensure the alignment marks on the sensor match the connector direction as specified in the manual.

6. 6

   Reassemble and Calibrate

   Reconnect the battery. Clear all error codes from the WLP/Control Panel.

7. 7

   Test Operation

   Perform a lifting calibration if required by the system, then test the tractor's rear lift using the cab controls to ensure the anomaly does not reappear.