CLAAS Id76BBh / 76BBh (738) – REH (A58) - Rear Lifting Module: Missing actual speed information over Powertrain CAN bus

The REH lifting module has not received the actual speed information for more than 1 second over the Powertrain CAN bus. As a result of this missing speed data, the tractor's skid control becomes inactive (or is deactivated if it was currently active).

• CLAAS Axion 850
• CLAAS Axion 840
• CLAAS Axion 830
• CLAAS Axion 820
• CLAAS Axion 810
• CLAAS Arion 640
• CLAAS Arion 630
• CLAAS Arion 620
• CLAAS Arion 610
• CLAAS Arion 540
• CLAAS Arion 530
• CLAAS Arion 520
• CLAAS Arion 510
• CLAAS Arion 430
• CLAAS Arion 420
• CLAAS Arion 410

1. 1

   Check the Powertrain CAN bus network wiring harness and connectors for continuity, shorts, or open circuits between the lifting module, the dashboard, and the speed sensor

2. 2

   Ensure the actual forward speed sensor (radar) (B230) is plugged in, undamaged, and has a clean line of sight

3. 3

   Verify the instrument panel module DBD (A101) is functioning and transmitting data

4. 4

   Verify the lifting module REH (A58) is receiving power and has secure connector seating

1. 1

   Visual Inspection

   Locate the actual forward speed sensor (radar) (B230) under the tractor. Clean the sensor face and inspect the wiring pigtail for physical damage, chafing, or corrosion.

2. 2

   Harness Continuity Test

   Using a multimeter, check the continuity of the Powertrain CAN bus lines (CAN-High and CAN-Low) between the B230 radar sensor, the A101 DBD instrument panel, and the A58 REH lifting module.

3. 3

   Check CAN Voltages

   At the A58 REH module connector, verify the Powertrain CAN bus voltages (CAN-Low should be approx. 2.3V, CAN-High should be approx. 2.7V).

4. 4

   Test the Radar Sensor

   If the CAN bus wiring is intact and the A101 instrument panel is functioning normally (no other CAN timeout codes present), the B230 radar sensor has likely failed and is no longer broadcasting the actual ground speed. Replace the B230 sensor.

5. 5

   Module Replacement (Last Resort)

   If the radar sensor is replaced and the wiring is perfect but the code persists, the A58 REH lifting module may have an internal fault preventing it from reading the CAN bus messages. Replace and program the A58 module.

6. 6

   Clear Codes

   Cycle the key and use the CLAAS Diagnostic System (CDS) or Win Metadiag to clear the inactive fault codes and test the skid control function.