CLAAS Id75C2h / 75C2h (303) – TR1 (A57-1) Transmission Control Module ("Auto 5"): Supply voltage measured on the forward gear solenoid valve when the driver is not controlled (setpoint PWM = 0)

The transmission control system is detecting a 12V supply voltage on the forward gear solenoid valve circuit even though the controller is commanding a 0% Pulse Width Modulation (PWM) signal (meaning the valve should be completely off). This indicates an electrical short to power (12V) somewhere in the circuit or an internal failure within the control module itself. When this code triggers, the machine will sound an audio warning and request an "ISC" (Interactive Speed Control) reset.

• CLAAS Axion 800 Series
• Axion 810
• Axion 850
• CLAAS Arion 600 Series
• Arion 610
• Arion 630
• Arion 640
• CLAAS Arion 400 Series
• Arion 410
• Arion 420
• Arion 430
• CLAAS Ares Series
• Ares 697 ATZ

1. 1

   Check for a possible 12V short circuit on the forward gear solenoid valve power supply harness

2. 2

   Check the connectors and continuity of the harnesses linking the transmission module to the solenoid valve for pinched wires, rubbed insulation, or water ingress

3. 3

   Test the Auto 5 module using the official CLAAS diagnostic breakout tool to determine if the module is internally shorted

1. 1

   Locate the Components

   Locate the TR1 (A57-1) "Auto 5" module (often located behind the seat on the control board, depending on the model) and the forward gear proportional solenoid valve (Component ID: Y327) on the transmission valve block.

2. 2

   Isolate the Harness

   Disconnect the harness at both the Y327 solenoid valve and the Auto 5 module.

3. 3

   Test for Short to Power

   Using a multimeter, check the signal wire for the forward gear solenoid for continuity to a 12V power source.

4. 4

   Repair Wiring (If Applicable)

   If a short to 12V is found in the harness, trace the wire to find the damaged section and repair or replace the harness.

5. 5

   Test/Replace the Auto 5 Module

   If the wiring harness tests perfectly fine, the internal driver inside the Auto 5 module has likely failed (shorted closed). Connect the CLAAS diagnostic tool (60 05 033 249) to verify the module's output. If the module is outputting voltage at a 0 PWM setpoint, the Auto 5 module must be replaced or sent out for electronic remanufacturing.

6. 6

   Recalibrate

   If the Auto 5 module is replaced, the new module must be programmed and the transmission clutches/valves must be recalibrated using the CLAAS Diagnostic System (CDS).