Case IH 5012 - UCM – UCM: Rear PTO shift - sensor error

The potentiometer of the PTO shift position sensor is failing to indicate the necessary movement data back to the controller when a PTO shift is commanded. Alternatively, under the Transmission (TCU) module, it can indicate the PTO clutch is slipping excessively for 5 seconds or longer.

• MAXXUM T4E
• Puma 115
• Puma 165
• Puma 180
• Puma 195
• Puma 210
• Puma 225
• Magnum MX210
• Magnum MX230
• Magnum MX255
• Magnum MX285
• Magnum 180
• Magnum 190
• Magnum 210
• Magnum 215
• Magnum 225
• Magnum 245
• Magnum 275
• Magnum 305
• Maxxum 100
• Maxxum 110
• Maxxum 115
• Maxxum 120
• Maxxum 125
• Maxxum 130
• Maxxum 140
• Steiger Series

1. 1

   Inspect the PTO shift position sensor (potentiometer) and its primary connector (X781) for physical damage, moisture, or corrosion

2. 2

   Check the wiring harness for continuity, shorts to ground, or open circuits through inline connectors (X783), transmission relays (X780, X782), and back to the UCM controller pins (X748)

3. 3

   Verify that the sensor is receiving the correct 5V reference voltage and ground from the UCM, and that the signal return wire is transmitting variable voltage as the shift mechanism moves

4. 4

   Verify that the PTO shift actuator and internal shift forks are not physically jammed, which would prevent the sensor from reading movement

5. 5

   If diagnosing the clutch slip variant of this code: check the PTO clutch hydraulic pressure and verify that the PTO speed sensors are reading correctly without dropping the signal

1. 1

   Safety First

   Turn off the engine, lower all equipment, and ensure all pressure is relieved from the hydraulic circuits before beginning work.

2. 2

   Locate the Sensor

   Locate the PTO shift position sensor on the rear PTO housing.

3. 3

   Removal

   Disconnect the electrical connector from the sensor. Unbolt the retaining hardware and carefully remove the faulty potentiometer/sensor from the housing.

4. 4

   Installation

   Install the new PTO shift position sensor, ensuring the mechanical linkage/pin aligns correctly with the sensor's internal sweep. Secure the mounting hardware.

5. 5

   Reconnect

   Plug the wiring harness back into the sensor, ensuring the weather seal clicks into place.

6. 6

   Calibration

   Turn the key to the ON position and enter the tractor's diagnostic menu (e.g., the 'H' Menu on the ADIC display). You must perform the Rear PTO Shift Calibration procedure so the UCM can learn the new sensor's physical end-stops.

7. 7

   Testing

   Clear the stored fault codes, start the tractor, and test the PTO engagement and shifting under a safe load to ensure the code does not return.