Case IH 3123 - UCM – Engine Control Module (ECM/ENG) or Universal Control Module (UCM): PTO Twist Sensor - Not Calibrated

The PTO twist sensor monitors the rotational twist/torque on the Power Take-Off (PTO) shaft to ensure it operates at the correct speeds and loads. This code is triggered when the system detects that the calibration value for the sensor is missing, or the stored calibration value is implausible (too high or too low).

• MAXXUM T4E
• Case IH Magnum Series (225, 235-340 Series 4)
• Case IH Puma Series (115-225, 180-260 CVX)
• Case IH Maxxum Series (100-140)
• Case IH Farmall Series (40-50 CVT, 75-120)

1. 1

   Verify PTO Status: Ensure the PTO is completely turned OFF. If the PTO is engaged or started during a calibration attempt, the calibration will abort and trigger this code.

2. 2

   Wiring and Connector Inspection: Check the wiring harness and connectors leading to the PTO twist sensor. Look for an open circuit, a short circuit to ground, or a short circuit to power.

3. 3

   Physical Inspection: Verify that the sensor is not physically damaged, loose, or incorrectly installed, which would cause the readings to be out of range during calibration.

1. 1

   Attempt Recalibration

   Enter the tractor's calibration menu via the instrument cluster or armrest display. Navigate to the PTO twist sensor calibration screen (often denoted by 'Pt' on the display during the sequence).

2. 2

   Execute Calibration

   Follow the on-screen prompts or hold the designated switch (e.g., the downshift button, depending on the model) to calibrate the sensor. Ensure the tractor is stationary and the PTO is disengaged.

3. 3

   Evaluate Results

   If the display alternates between 'Pt' and a valid calibration value, the procedure was successful. Clear the fault codes and test the PTO operation.

4. 4

   Replace Sensor (If Calibration Fails)

   If the calibration value remains out of range, or if the sensor has an internal open/short circuit, the PTO twist sensor must be replaced.

5. 5

   Final Calibration

   After installing a new sensor, you must perform the PTO twist sensor calibration procedure again to marry the new sensor to the UCM/ECM.