CLAAS Id764Fh / 764Fh (448) – TR2 (A57-2) Transmission Module / Auto 5: Supply voltage measured on solenoid valve SV1 when the driver is not controlled (setpoint PWM = 0).

The transmission control unit is detecting a 12V supply voltage on the circuit for solenoid valve SV1 even though the controller is not commanding the valve to open (Pulse Width Modulation setpoint is at 0%). This typically indicates a short-to-power (12V) in the wiring harness or an internal failure within the control module itself.

• CLAAS Axion 800 Series
• Axion 810
• Axion 850
• CLAAS Arion 600 / 500 Series
• Arion 640
• Arion 630
• Arion 610
• Arion 510
• CLAAS Arion 400 Series
• Arion 430
• Arion 420
• Arion 410
• CLAAS Axos

1. 1

   Check for a possible 12 V short circuit on the solenoid valve power supply harness leading to SV1.

2. 2

   Inspect the solenoid valve SV1 (Component designation: Y335-1, which controls the 'Ratio under torque' for the Hexashift transmission).

3. 3

   Test the 'Auto 5' module (TR2 / A57-2) using CLAAS special tool n° 60 05 033 249 (Auto 5 input/output control harness/tool).

1. 1

   Safety First

   Turn off the tractor, remove the key, and ensure the machine is safely secured.

2. 2

   Locate Components

   Locate the TR2 (A57-2) Auto 5 module (frequently installed behind the seat on the control board) and the Y335-1 (SV1) solenoid valve on the transmission hydrostatic/Hexashift unit.

3. 3

   Inspect Wiring

   Visually inspect the wiring harness running between the TR2 module and the Y335-1 solenoid. Look for chafing, melted insulation, or pinched wires that could introduce a 12V short to the circuit.

4. 4

   Test for Short to Power

   Disconnect the harness at the SV1 solenoid and at the TR2 module. Using a multimeter, check the SV1 signal wire for continuity to any 12V power source. If a short is found, repair or replace the damaged section of the harness.

5. 5

   Test the Control Module

   If the wiring harness is intact and shows no short circuits, connect CLAAS tool n° 60 05 033 249 to the Auto 5 module to verify its outputs. If the module is internally shorted and sending voltage when the PWM setpoint is 0, the module is defective.

6. 6

   Replace and Calibrate

   Change the Auto 5 module if required. Note that a replacement Auto 5 module must be programmed and taught its specific function (transmission control) using the CLAAS Diagnostic System (CDS).