John Deere 523590.13 – TCU: Forward Pedal Not Calibrated

The Transmission Control Unit (TCU) has detected that the forward pedal position sensor is not calibrated. The voltage signal from the sensor, which corresponds to the pedal's position, is outside the expected range stored in the controller's memory. Without a correct calibration, the TCU cannot accurately determine the operator's command for forward movement, which can lead to improper or no operation of the machine's hydrostatic transmission.

• 3320
• 3520
• 3720
• 4120
• 4210
• 4310
• 4320
• 4410
• 4520
• 4610
• 4710
• 4720

1. 1

   Access the diagnostic trouble codes through the tractor's display to confirm that 523590.13 is active

2. 2

   Check the wiring harness and connectors between the forward pedal sensor (potentiometer) and the transmission controller for any visible damage, corrosion, or loose connections

3. 3

   Measure the sensor signal voltage using a multimeter. The sensor receives a 5-volt reference, and the expected signal range is approximately 1.8 volts at one end of travel and around 4.8 volts at the other

4. 4

   Examine the pedal assembly for any mechanical issues, such as worn bushings or sticking linkages, that could prevent the pedal and sensor from moving through their full range of motion

1. 1

   Perform manual calibration

   Unplug the forward pedal sensor. Turn the ignition key switch to the 'ON' position and wait for 5 seconds. Turn the key switch 'OFF' and wait for 5 seconds. Plug the sensor back in. Turn the key switch back to the 'ON' position and wait for 5 seconds. Firmly press the forward pedal to its maximum travel and hold it for 5 seconds. Release the pedal. Turn the key switch 'OFF' and wait for 5 seconds. Start the tractor and check if the code has cleared and the pedal is responsive.

2. 2

   Access and adjust the sensor

   If calibration fails, access the sensor under the operator platform by removing the pedal cover. Loosen the two mounting bolts (often 10mm) and minutely rotate the sensor to bring its voltage reading into the correct 1.8V to 4.8V range. Retighten the bolts and attempt the calibration procedure again.

3. 3

   Replace the sensor

   If the sensor is faulty and cannot be adjusted into the proper voltage range, disconnect the electrical connector, remove the mounting bolts, and install a new sensor. Ensure it is securely fastened.

4. 4

   Recalibrate new sensor

   After replacing the sensor, a calibration procedure must be performed to store the new sensor's values in the TCU.