CLAAS Id76A7h / 76A7h (718) – REH (A58) Rear Lifting Module: Missing engine running information on Powertrain CAN bus and missing alternator D+ load signal

The REH (A58) lifting module does not receive any engine running information on the Powertrain CAN bus (or this information is in error on the Powertrain CAN bus), and the alternator’s D+ load signal is missing. The rear lifting function becomes inactive/locked.

• Axion 800
• Axion 810
• Axion 820
• Axion 830
• Axion 840
• Axion 850
• Axion 920
• Axion 950
• Arion 410
• Arion 430
• Arion 510
• Arion 610
• Arion 630
• Arion 640

1. 1

   The Powertrain CAN bus network: Check for communication errors, shorts, or open circuits.

2. 2

   The Alternator D+ Signal: Verify the physical D+ (charge/engine running) signal wire from the alternator.

3. 3

   The TR2 transmission module (A57-2): Ensure it is communicating properly on the CAN bus.

4. 4

   The engine module ENG (A15): Verify it is broadcasting engine running data.

5. 5

   The lifting module REH (A58): Check its power, ground, and CAN connections.

1. 1

   Verify the Alternator D+ Circuit

   Check the D+ terminal for output when the engine is running. Inspect the wiring harness from the alternator to the main cab harness for breaks, corrosion, or loose connectors.

2. 2

   Inspect Harnesses and Connectors

   Check the connectors and continuity of the harnesses linking the REH (A58), ENG (A15), and TR2 (A57-2) modules. Look for pushed pins, moisture intrusion, or chafed wires.

3. 3

   Test Power and Ground

   Check the sources of energy for the REH (A58) module. Verify all related fuses, main power supply relays, and ground straps are secure and providing proper voltage.

4. 4

   Test CAN Bus Integrity

   Measure the resistance of the Powertrain CAN bus (should be approximately 60 ohms with batteries disconnected). Check for short-circuits to ground or power on the CAN-High and CAN-Low lines.

5. 5

   Software/Calibration Check

   If the wiring is fully intact, check the compatibility of the program versions, settings, and calibration of the ENG, TR2, and REH modules using the CLAAS Diagnostic System (CDS).

6. 6

   Component Replacement

   If a module is found to be internally shorted or failing to broadcast/receive on the CAN bus despite good power, ground, and wiring, replace the faulty component (Alternator or REH A58 module).