New Holland 73 – TRANS: Park Brake Request Active After Calibration

The transmission control module has exited a calibration procedure, but it still detects that the park brake is engaged. The park brake signal should clear after the calibration mode is complete. This active park brake request may prevent normal operation of the machine until the park brake is released.

• T7.200
• T7.210
• T7.220
• T7.235
• T7.250
• T7.260
• T7.270
• T7030
• 8670
• 8770
• 8870
• 8970
• TM115
• TM125
• TM135
• TM150
• TS90
• TS100
• TS110
• TS115

1. 1

   Verify the fault code is present in the diagnostic menu (often the 'H' menu).

2. 2

   Check for other active fault codes, especially those related to the park brake switch or solenoid (e.g., code 4431).

3. 3

   Inspect the park brake switch by physically actuating it to ensure it moves freely and is not stuck.

4. 4

   Use the tractor's built-in switch diagnostic mode (often 'H5') to check if the controller registers the switch changing state.

5. 5

   Visually inspect the wiring harness and connectors for the park brake switch and solenoid for damage, corrosion, or loose connections.

6. 6

   Ensure the battery voltage is stable and within correct specifications to rule out ghost faults.

1. 1

   Attempt to clear fault

   Ensure the park brake is disengaged, cycle the key, and attempt to clear the fault codes using the diagnostic menu (often 'HC'). If the fault remains, proceed to the next step.

2. 2

   Test park brake switch

   Disconnect the park brake switch and use a multimeter to test for continuity. The switch should show a change in state (open to closed, or vice-versa) when actuated. Replace the switch if it fails this test.

3. 3

   Test park brake circuit

   Check for continuity between the transmission controller and the park brake switch connector. Check for a short to ground or a short to power in the signal wire from the switch to the controller.

4. 4

   Test park brake solenoid

   On models with an electro-hydraulic park brake, listen for a click from the solenoid when engaged/disengaged. Test for resistance or activate manually to confirm operation. Replace if faulty.

5. 5

   Re-run transmission calibration

   After repairs, re-run the transmission calibration procedure. Ensure all conditions (oil temperature, engine RPM) are met, and that the park brake is engaged before starting and disengaged after.