CLAAS Id7690h / 7690h (517) – TR3 (A57-3): The automatic hand brake disengaged sensor is locked in the engaged position

Because the system cannot verify that the hand brake has disengaged, the automatic hand brake becomes inactive. As a result, the operator cannot electronically engage or disengage the automatic hand brake.

• Axion 810–850
• Axion 920–950
• Arion

1. 1

   Check for a possible open circuit in the wiring harness of the automatic hand brake sensor (designated in the wiring diagram as component Z158).

2. 2

   Inspect and test the automatic hand brake engaged sensor (Z158) itself.

3. 3

   Check for a possible mechanical problem on the automatic hand brake assembly that might be physically locking the mechanism.

4. 4

   Check the "Auto 5" module using the specified diagnostic procedure/tool (referenced as n° 60 05 033 249).

1. 1

   Manual Override

   Because the electronic control is inactive, you must first use the mechanical release screw to manually disengage the automatic hand brake so the tractor can be moved or serviced.

2. 2

   Wiring Inspection

   Trace the wiring harness from the TR3 (A57-3) module to sensor Z158. Repair any open circuits, broken wires, or corroded connectors.

3. 3

   Sensor Replacement

   If the wiring is intact, test sensor Z158. If it is internally shorted or mechanically stuck in the engaged position, replace the sensor.

4. 4

   Mechanical Inspection

   Inspect the hand brake mechanism for binding, debris, or mechanical failure preventing the brake from physically disengaging.

5. 5

   Module Replacement

   If the sensor, wiring, and mechanical components are all functioning correctly, the fault may lie within the "Auto 5" electronic module. Replace the module if it fails diagnostic testing.