Massey Ferguson E974.03 – Engine Control Unit (ECU) / AGCO SISU POWER EEM4: Hand Throttle Potentiometer, Voltage Too High

The control unit measures a voltage in excess of 4.7 volts at the signal input of the hand throttle potentiometer (B96), indicating a short circuit to a positive lead, an open circuit in the sensor wiring, or a problem with the ground connection.

• 7616
• 5612
• 7622
• Interim Tier 4 (2012-2015)
• 7614
• 5611
• 7615
• 5610
• 5613
• 7620
• 5609
• 7618
• 5608
• 7619
• 7626
• 7624
• 5600 Series
• 5700 Series
• 5710
• 5713 SL
• 6400 Series
• 6600 Series
• 6700 Series
• 7400 Series
• 7600 Series
• 7700 Series
• 8400 Series
• 8600 Series
• 8700 Series
• MF 2850E

1. 1

   Visually inspect the wiring harness and connectors leading to the hand throttle potentiometer for physical damage, rubbing, or corrosion

2. 2

   Use a multimeter to verify the throttle sensor power supply is within the correct operating range (typically 5V) and verify that the ground connection to the sensor is solid with no excessive resistance

3. 3

   Perform a continuity test on the signal wire (e.g., lead 6018) to check for an open circuit or a short to a positive voltage source

4. 4

   If wiring, power, and ground test normal, temporarily connect a known-good throttle sensor to see if the fault clears (confirms internal sensor failure)

1. 1

   Power Down

   Turn off the tractor ignition and disconnect the battery to prevent electrical spikes during service.

2. 2

   Access the Sensor

   Locate the hand throttle potentiometer (B96) on the operator's right-hand console or armrest.

3. 3

   Disconnect

   Unplug the wiring harness connector from the throttle sensor.

4. 4

   Repair Wiring

   If your diagnostic checks revealed a broken wire, bad ground, or short circuit, repair the harness as necessary.

5. 5

   Replace Sensor

   If the wiring is intact, unbolt/unclip the defective hand throttle potentiometer switch and install the OEM replacement part.

6. 6

   Reassemble

   Reconnect the wiring harness and reconnect the battery.

7. 7

   Calibration

   A throttle pedal/sensor calibration is strictly required after replacing the potentiometer. This is done via the tractor's service menu or a diagnostic service tool (like WinEEM4) so the ECU can learn the new sensor's minimum and maximum voltage sweep.

8. 8

   Clear Codes

   Clear the E974.03 / SPN 974 fault code from the ECU and test the hand throttle operation to ensure engine RPM responds correctly.