Case IH 5007 - UCM – UCM: Rear PTO solenoid - open circuit or short circuit to ground

This fault code indicates an electrical failure in the rear Power Take-Off (PTO) control circuit. The system has detected that the circuit to the rear PTO solenoid is either open (broken wire, disconnected plug, or failed solenoid coil) or shorted to ground.

• MAXXUM T4E
• Puma series (145, 165, 180, 195, 210, 225, CVX)
• Magnum series (210, 220, 235-340 Series 4)
• Maxxum series
• Steiger series
• Farmall series

1. 1

   Inspect the wiring harness between the UCM and the Rear PTO Solenoid for chafed wires shorting to the tractor chassis (ground) or broken wires causing an open circuit.

2. 2

   Check the specific connector at the solenoid (often designated as X278, X276, or X-159) for corrosion, pushed-out pins, or moisture.

3. 3

   Disconnect the rear PTO solenoid and measure the resistance across the solenoid coil pins. An infinite reading indicates an internal open circuit, while a reading of zero indicates an internal short.

4. 4

   Verify that the UCM is receiving proper voltage and check for any blown fuses related to the PTO circuit.

1. 1

   Disconnect Power

   Turn off the tractor and disconnect the battery to prevent electrical spikes.

2. 2

   Repair Wiring

   If the diagnostic checks revealed a broken or shorted wire in the harness, repair the wire using proper weather-sealed splices, or replace the damaged connector pigtail.

3. 3

   Replace the Solenoid

   If the wiring is intact but the solenoid failed the resistance test, remove the retaining nut/bolt holding the rear PTO solenoid coil to the valve body. Slide the old solenoid off and install the new one. Reconnect the wiring harness.

4. 4

   Calibrate the PTO

   Following the replacement of the solenoid (or if a new UCM is fitted), an automatic calibration procedure must take place. The system will automatically detect the EDC/PTO controls. The specific calibration values (typically between 100 to 420 for the rear PTO solenoid) are generated during an automatic calibration that is initiated when the PTO is first started.