CLAAS Id76A3h / 76A3h (714) – REH (A58): Voltage of the external lifting controls signal non valid

The rear lifting function becomes inactive. This code triggers when the system detects an out-of-range, missing, or incoherent voltage signal coming from the external fender-mounted switches used to raise or lower the rear hitch.

• CLAAS Axion 800 Series (810, 820, 830, 840, 850, 870)
• CLAAS Axion 900 Series (920, 930, 940, 950)
• CLAAS Arion 400, 500, and 600 Series (410, 430, 510, 640)

1. 1

   Check External Controls (S181 and S182): S181 is the external lifting UP contact, and S182 is the external lifting DOWN contact.

2. 2

   Check the REH (A58) Module: Verify the module is receiving power and communicating properly.

3. 3

   Harness and Continuity: Check the connectors and continuity of the wiring harnesses linking the external switches to the REH module.

4. 4

   Short/Open Circuits: Test the wiring for any short-circuits to ground/power or open circuits.

5. 5

   Component Resistance: Check the resistance of the S181 and S182 switches to ensure they are operating within specification.

6. 6

   Power Sources: Check the sources of energy, including fuses, power supply, and ground connections to the switches and the REH module.

1. 1

   Visual Inspection

   Inspect the rear fender external lift switches (S181 and S182) for physical damage, water ingress, or heavy dirt accumulation, which is common given their exposed location.

2. 2

   Wiring Test

   Disconnect the switches and use a multimeter to test the wiring harness back to the REH (A58) module. Look for continuity and ensure there is no short to ground.

3. 3

   Switch Test

   Test the S181 and S182 switches with a multimeter. They should show a clear change in resistance/continuity when pressed. If the voltage signal is erratic or dead, the switch has failed.

4. 4

   Replace Faulty Component

   If a switch is faulty, replace it. If the wiring is damaged (e.g., rubbed through on the chassis or fender), repair the harness.

5. 5

   Module Verification

   If the switches and wiring test perfectly, the fault lies within the REH (A58) module itself. Check its 12V supply and 10V regulated voltage. If the module has internally failed, it must be replaced and reprogrammed/calibrated using the CLAAS Diagnostic System (CDS).

6. 6

   Clear Codes

   After repair, clear the fault codes and test the external lifting controls to ensure the rear hitch operates correctly.