Massey Ferguson 3.00.9E – MFA (Multi-Function Armrest): Issue With Hand Throttle On Arm Rest Signal Voltage

The signal voltage coming from the hand throttle potentiometer is out of the expected or calibrated range (either too high, too low, or erratic). When this occurs, the controller cannot accurately determine the operator's requested engine speed, which may result in restricted operating modes or the tractor retaining its last known speed setting.

• 5710SL
• 5711SL
• 5712SL
• 5713SL
• T4
• 4707
• 4708
• 4709
• 4710
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 7714
• 7715
• 7715S
• 7716
• 7718
• 7719
• 7720
• 7722
• 7724
• 7726
• 8670
• 8690

1. 1

   Inspect the wiring harness and connectors between the hand throttle potentiometer (sensor X122 or B035) and the MFA controller for chafed wires, loose pins, or corrosion inside the armrest console.

2. 2

   Test the sensor supply voltage (typically 5V or 8.5V) and the ground circuit at the potentiometer connector.

3. 3

   Monitor the signal voltage wire with a multimeter while slowly moving the hand throttle from the minimum to the maximum position. The voltage should scale smoothly without any dropouts, spikes, or dead spots.

4. 4

   Attempt to recalibrate the hand throttle. A sensor that has drifted out of its learned parameters can trigger an out-of-range voltage fault.

1. 1

   Disconnect Power

   Turn off the ignition and disconnect the tractor's battery to prevent electrical shorts.

2. 2

   Access the Sensor

   Disassemble the right-hand Multi-Function Armrest (MFA) console plastics to expose the underside of the hand throttle lever and its integrated potentiometer.

3. 3

   Remove the Faulty Unit

   Disconnect the electrical harness connector from the hand throttle. Remove the retaining screws or clips holding the throttle assembly in place and extract it from the armrest.

4. 4

   Install the New Part

   Seat the replacement hand throttle potentiometer into the armrest console and secure it with the mounting hardware. Reconnect the electrical harness.

5. 5

   Reassemble

   Reinstall the armrest console plastics and reconnect the tractor's battery.

6. 6

   Perform Calibration (Code 4002)

   Enter the calibration menu on the dashboard. Turn the hand throttle to the maximum position and press 'Return' (or the confirmation button) to confirm. Turn the hand throttle to the minimum position and press 'Return' to confirm. If successful, the system will display 'O.K.'. Turn the ignition key to the '0' (OFF) position and wait for the system to power down to save the new settings.

7. 7

   Clear Codes

   Turn the tractor back on and use the dashboard or the AGCO Electronic Diagnostic Tool (EDT) to clear the 3.00.9E fault code. Test the throttle operation.