Fendt 4.1.34 – Transmission Control Module (Twin EST Modules): Cruise control' key on membrane keypad — Signal fault

The control system is not receiving a valid electrical signal from the cruise control button located on the tractor's membrane keypad, causing the cruise control function to be disabled and unavailable to the operator.

• 409 Vario
• 410 Vario
• 411 Vario
• 412 Vario
• 711 Vario
• 712 Vario
• 714 Vario
• 715 Vario
• 716 Vario
• 717 Vario
• 718 Vario
• 916 Vario
• 920 Vario
• 924 Vario
• 926 Vario
• 930 Vario
• Fendt Vario
• Fendt Favorit 900 series

1. 1

   Inspect the membrane keypad on the control console/armrest for physical wear, deep scratches, tears, or signs of moisture ingress.

2. 2

   Attempt to clear the fault code via the tractor's on-board information system terminal to determine if it is an intermittent signal drop or a hard fault.

3. 3

   Access the back of the keypad/console and check the ribbon cable and connector linking the membrane keypad to the Transmission Control Module (EST) for tight seating, pinching, or corrosion.

4. 4

   Verify the voltage and continuity on the signal circuit between the keypad and the EST module using the transmission control electrical diagram to rule out a damaged wiring harness.

1. 1

   Preparation

   Turn off the tractor ignition and disconnect the battery to prevent any electrical shorts or accidental module damage.

2. 2

   Disassembly

   Carefully unscrew and remove the plastic trim/bezel on the control console or armrest to expose the electronic module that houses the membrane keypad.

3. 3

   Disconnection

   Gently unlatch and unplug the ribbon cable that connects the membrane keypad to the underlying circuit board.

4. 4

   Removal

   Carefully peel the defective membrane keypad off the console housing.

5. 5

   Cleaning

   Thoroughly clean the plastic mounting surface with a mild solvent (like isopropyl alcohol) to remove all residual adhesive, grease, and dirt. The surface must be completely smooth and dry.

6. 6

   Installation

   Peel the backing off the new membrane keypad. Carefully route the new ribbon cable through the slot in the housing, then align the keypad and press it firmly into place to ensure a watertight seal.

7. 7

   Reconnection

   Plug the new ribbon cable into the circuit board connector and lock it in place.

8. 8

   Reassembly

   Reinstall the console trim and reconnect the tractor's battery.

9. 9

   Testing

   Turn on the ignition, clear the stored 4.1.34 fault code, and test the cruise control button to ensure the function is restored.