Challenger D151 – Dash: Too High Speed Tractor

The tractor's control system has detected a vehicle speed that is excessively high. This is a safety-related fault that will often prevent the tractor from moving. The underlying condition is typically a malfunction in the speed sensing system, causing the tractor to register a high rate of speed (e.g., 62.4 MPH) even when the machine is completely stationary.

• AGCO RT100
• Challenger 35
• Challenger 45
• Challenger MT765C
• Challenger MT700 Series
• Challenger MT200 Series
• Challenger MT400 Series
• Challenger MT500 Series
• Challenger MT600 Series
• CAT Challenger 65E
• CAT Challenger 75C
• CAT Challenger 75D
• CAT Challenger 75E
• CAT Challenger 85C
• CAT Challenger 85D
• CAT Challenger 85E
• CAT Challenger 95E

1. 1

   Retrieve all fault codes using the diagnostic display to check for accompanying transmission or speed sensor issues.

2. 2

   Observe the speedometer on the instrument panel while stationary; a high reading confirms a faulty speed sensor signal.

3. 3

   Visually inspect wiring harnesses and connectors for the engine, transmission, and ground speed/radar sensors for damage, corrosion, or loose connections.

4. 4

   Check fuses related to the instrument cluster and transmission controllers.

5. 5

   Perform a full system reboot by turning the tractor off, waiting for systems to power down, and cycling the main battery disconnect switch to clear erroneous faults.

1. 1

   Identify faulty sensor

   Determine if the transmission output speed sensor or ground speed radar sensor is at fault based on accompanying codes. Location varies by model (e.g., lower center housing on Challenger 35/45, front lower right of center output shaft on MT765).

2. 2

   Remove suspect sensor

   Disconnect the electrical connector. Clean the surrounding area to prevent debris from entering the housing, then unthread and remove the sensor.

3. 3

   Install new sensor

   Thread in the replacement speed sensor and tighten to the manufacturer's specified torque. Reconnect the electrical harness.

4. 4

   Clear codes and calibrate

   Clear all fault codes from the system. Perform a speed sensor or system calibration if required by your specific model's service manual.

5. 5

   Test operation

   Start the tractor and verify the speedometer reads 0 when stationary and the D151 code does not return. Test drive to ensure proper transmission shifting and speed readout.