Massey Ferguson 29.04 – ECU: Engine Throttle Sensor Voltage Issue

The voltage signal coming from the hand throttle potentiometer has dropped below the minimum acceptable threshold. This condition typically indicates a short to ground, an open circuit in the sensor wiring, or an internal failure of the potentiometer itself.

• 4710
• 7724S
• 5712SL
• Interim Tier 4 (2012-2015)
• 7722
• 7722S
• 7615
• 5613
• 5713SL
• 7720S
• 7716
• 7718
• T4
• 7715
• 5710SL
• 7726
• 7616
• 7618
• 5608
• 4708
• 7619
• 7626
• 7726S
• 7624
• 4707
• 4709
• 5711SL
• 7614
• 7718S
• 5610
• 7620
• 7719
• 7714
• 7716S
• T4 (2015-2021)
• 5612
• 7622
• 7720
• Tier 4 (2015-2021)
• 5611
• 7715S
• 5609
• 7724
• 5709SL
• 6400 Series
• 6600 Series
• 6700 Series
• 7400 Series
• 8400 Series
• 8600 Series
• 8700 Series

1. 1

   Inspect the wiring harness and connectors between the hand throttle potentiometer and the ECU for chafed wires, corrosion, or loose pins.

2. 2

   Verify the sensor is receiving the correct reference voltage (usually 5V) from the ECU and that the ground circuit is intact.

3. 3

   Test the signal wire from the sensor connector back to the ECU for continuity and ensure it is not shorted to the chassis ground.

4. 4

   Perform a potentiometer sweep test by back-probing the signal wire and slowly moving the hand throttle lever from idle to full throttle to check for smooth voltage increase without drop-offs.

1. 1

   Disconnect Power

   Turn off the ignition and disconnect the negative battery cable to protect the ECU.

2. 2

   Wiring Repair

   If the diagnostic checks revealed a broken wire or short to ground in the harness, repair the damaged section using proper soldering and heat-shrink techniques, or replace the affected harness pigtail.

3. 3

   Sensor Replacement

   If the wiring is intact but the sensor failed the sweep test, locate the hand throttle potentiometer assembly in the cab console.

4. 4

   Removal

   Disconnect the electrical connector from the sensor. Remove the retaining screws/clips holding the potentiometer to the hand throttle lever assembly and remove the faulty unit.

5. 5

   Installation

   Install the new OEM throttle sensor, secure the fasteners, and plug in the electrical connector.

6. 6

   Reassembly & Calibration

   Reconnect the battery. Turn the key to the ON position. Use a compatible diagnostic scan tool to clear the 000029.04 fault code from the ECU.

7. 7

   Testing

   Perform any required throttle calibration procedures via the dash or diagnostic tool (if specified for your exact model). Start the tractor and verify smooth engine RPM response when using the hand throttle.