CLAAS 75FDh – TR1 (A57-1): Simultaneous Forward and Reverse Signal

The transmission control module has detected an illogical input from the forward/reverse shuttle lever (reverser lever S171). The system is receiving simultaneous signals for both forward and reverse, which is an invalid state. As a safety precaution, this condition prevents the HEXASHIFT transmission from engaging any gear.

• Arion 640-510
• Arion
• Axion

1. 1

   Note all active and stored error codes to see if other related faults are present, as an inconsistent signal can trigger multiple codes.

2. 2

   Visually inspect the wiring harness and connectors between the reverser lever (on the steering column) and the TR1 transmission module for damage, corrosion, or loose connections.

3. 3

   Check the lever's wiring harness for short circuits to power or ground, and verify there are no open circuits (broken wires or unplugged connectors).

4. 4

   Verify the power supply and ground connections to the TR1 module.

5. 5

   Check the resistance of the component, if specifications are available.

6. 6

   Test the reverser lever (S171) output signals to ensure they correspond correctly to the lever's position (Neutral, Forward, Reverse) without overlap.

1. 1

   Disconnect battery

   Disconnect the tractor's battery before beginning any electrical repairs.

2. 2

   Access the reverser lever

   Remove the steering column shrouds and any other panels necessary to gain access to the reverser lever switch and its electrical connector.

3. 3

   Repair wiring harness

   If visual and electrical checks reveal a wiring fault (short or open circuit), repair or replace the damaged section of the harness.

4. 4

   Replace reverser lever

   If diagnostic checks point to an internal fault within the reverser lever assembly (multiple states active simultaneously), unbolt it from the steering column, disconnect the single electrical connector, and replace the lever.

5. 5

   Reassemble and test

   Reconnect the battery, clear all fault codes using a diagnostic tool, start the tractor, and operate the reverser lever to ensure gears engage correctly without the 75FDh code reappearing.