Massey Ferguson T4122 – Transmission Control Unit (TCU) / TRANS: Issue With Signal Voltage From Foot Throttle Sensor DYNA VT (TRANS)

The signal voltage coming from the foot throttle pedal potentiometer is outside of its normal operating range (typically dropping below 0.5V or exceeding 4.5V). This causes a signal error, meaning the controller cannot accurately determine the operator's requested speed, which may force the tractor into a limited operating mode or inhibit RPM requests.

• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• Interim Tier 4 (2012-2015)
• 7600 Series
• 5600 Series
• 6600 Series
• 8600 Series

1. 1

   Inspect the wiring harness and the connector at the foot throttle sensor for physical damage, corrosion, or loose pins

2. 2

   Perform a voltage sweep test using a multimeter or AGCO Electronic Diagnostic Tool (EDT) to monitor signal voltage while slowly depressing the pedal; it should scale smoothly between 0.5V and 4.5V without dead spots or erratic jumps

3. 3

   Ensure the sensor is receiving a steady 5V reference supply and has a solid ground (a short to ground or power in the harness will trigger this code)

4. 4

   Check for accompanying dashboard (Dash) codes such as D133 (Signal voltage too high) or D134 (Signal voltage too low)

1. 1

   Disconnect Power

   Turn off the tractor and disconnect the battery to prevent electrical shorts during the repair.

2. 2

   Access the Sensor

   Locate the foot throttle potentiometer assembly, which is mounted at the base of the throttle pedal inside the cab.

3. 3

   Removal

   Unplug the electrical harness connector from the sensor. Remove the mounting bracket bolts/screws securing the sensor to the pedal assembly.

4. 4

   Installation

   Mount the new throttle sensor in place and secure the hardware. Reconnect the electrical harness.

5. 5

   Reconnect Power

   Reconnect the tractor's battery.

6. 6

   Calibration

   A new throttle pedal sensor must be calibrated to the transmission control module so it learns the new minimum and maximum travel limits. This is done by executing the "Calibration of the throttle pedal sensor" procedure, which typically requires the AGCO Electronic Diagnostic Tool (EDT) or navigating to the specific calibration menu on the tractor's Datatronic/dashboard display.