CLAAS Id75C9h / 75C9h (310) – TR1 (A57-1) Transmission Module: The actual current measured on the reverse gear solenoid valve return is less than the setpoint value

The transmission control module is commanding the reverse gear proportional solenoid valve to open, but the electrical current returning to the module is lower than expected. This typically indicates high resistance in the circuit, a failing solenoid coil, a short to ground, or a wiring harness issue. This fault does not trigger an audio warning and does not request an "ISC" reset.

• CLAAS Axion 800 Series (810, 850)
• CLAAS Arion 600 Series (610, 630, 640)
• CLAAS Arion 500 Series (510)
• CLAAS Arion 400 Series (410, 430)

1. 1

   Verify that the tractor's battery voltage is sufficient and stable.

2. 2

   Check for possible high resistance or corrosion on the reverse gear solenoid valve supply harness.

3. 3

   Check for a possible short circuit to earth (ground) on the solenoid valve wiring.

4. 4

   Measure the internal resistance of the reverse gear solenoid valve winding.

5. 5

   Test the "Auto 5" module using CLAAS diagnostic tool n° 60 05 033 249 (if available to your dealer/shop).

1. 1

   Locate the Component

   Identify the reverse gear proportional solenoid valve on the transmission valve block. In CLAAS wiring diagrams, this component is designated as Y328.

2. 2

   Inspect Connectors

   Disconnect the harness at the Y328 solenoid and at the TR1 (A57-1) transmission module. Inspect the pins for corrosion, pushed-out terminals, or moisture ingress.

3. 3

   Test Harness Continuity

   Using a multimeter, test the continuity of the wires between the TR1 module and the Y328 solenoid. Ensure there are no open circuits or short-circuits to the chassis ground.

4. 4

   Test the Solenoid

   Measure the resistance across the pins of the Y328 solenoid valve. If the resistance is out of specification (indicating an open coil or internal short), the solenoid valve must be replaced.

5. 5

   Check Power and Ground

   Verify that the fuses and power supply to the transmission module are intact.

6. 6

   Replace and Calibrate

   If the solenoid is found to be faulty, replace it. Check if compatibility of program versions, settings, or transmission calibration is required after replacement.