Massey Ferguson 3.00.9D – MFA: Issue With Hand Throttle On Arm Rest Signal Voltage (MFA)

This indicates a signal voltage error (such as an out-of-range voltage, open circuit, or short circuit) coming from the hand throttle potentiometer located on the tractor's armrest. When this code is active, the controller is receiving an implausible or missing electrical signal from the throttle position sensor, which can result in restricted engine RPM control or the tractor defaulting to the foot throttle/limp mode.

• 5710SL
• 5711SL
• 5712SL
• 5713SL
• T4
• 4707
• 4708
• 4709
• 4710
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 5709S to 5713SL
• 6445 to 6499
• 6612 to 6616
• 6712S to 6718S
• 7465 to 7499
• 7614 to 7626
• 7714 to 7726
• 8450 to 8740

1. 1

   Inspect the wiring harness connecting the hand throttle potentiometer to the MFA board inside the armrest for pinched wires, loose connector pins, or chafing.

2. 2

   Use a multimeter to verify the reference voltage reaching the potentiometer and check the signal return wire for smooth voltage sweeps as the throttle is moved. Dead spots or erratic voltage jumps confirm a failed potentiometer.

3. 3

   Attempt to recalibrate the hand throttle using the tractor's terminal or the AGCO Electronic Diagnostic Tool (EDT) (calibration code 4002). A lost calibration can sometimes trigger out-of-range voltage codes.

1. 1

   Power Down

   Turn off the ignition and disconnect the battery to prevent electrical shorts while working inside the armrest.

2. 2

   Disassemble the Armrest

   Carefully remove the covers/trim of the Multifunction Armrest (MFA) to access the internal controls.

3. 3

   Remove the Faulty Sensor

   Locate the hand throttle potentiometer switch assembly. Disconnect its electrical harness and unbolt/unclip it from the throttle lever mechanism.

4. 4

   Install the New Part

   Mount the replacement potentiometer (4274087M1) and reconnect the wiring harness.

5. 5

   Reassemble

   Reinstall the armrest covers and reconnect the tractor's battery.

6. 6

   Calibrate the New Throttle

   Turn the ignition ON. Access the tractor's diagnostic/calibration menu (via the Datatronic screen or AGCO EDT). Initiate the hand throttle calibration procedure. Move the hand throttle to the maximum position and confirm/save. Move the hand throttle to the minimum position and confirm/save. Cycle the ignition key to the '0' (OFF) position to lock in the new sensor settings.

7. 7

   Clear Codes

   Clear the 3.00.9D fault code from the MFA memory and test the tractor to ensure normal throttle response.