Case IH 5011 - UCM – UCM: Rear PTO shift motor – short circuit

The control module has detected an electrical short circuit, an abnormal current draw, or a lack of expected current in the circuit that controls the rear Power Take-Off (PTO) shift motor or solenoid.

• MAXXUM T4E
• Case IH Puma series (165, 180, 195, 210, 225)
• Case IH Magnum series (235-340, MX, and TG series)
• Case IH Maxxum series
• Case IH Steiger series

1. 1

   Inspect the connector ends at the PTO solenoid and the UCM for damaged, bent, or dislocated pins

2. 2

   Disconnect the PTO solenoid and measure its internal resistance with a multimeter (should be 6.0 to 6.8 ohms at 25°C/70°F)

3. 3

   Trace the wiring harness from the UCM to the PTO solenoid, looking for rubbed-through insulation causing a short to ground or wires touching each other

4. 4

   Test the cab and fender PTO switches for voltage leaks (e.g., showing voltage on the 'no voltage' side), which can cause the controller to abort initialization

1. 1

   Disconnect Power

   Always disconnect the negative battery cable before working on the tractor's electrical system to prevent accidental shorts or spikes.

2. 2

   Locate the Component

   Locate the rear PTO shift motor/solenoid valve on the rear PTO housing/valve block.

3. 3

   Disconnect and Isolate

   Unplug the wiring harness connector from the PTO solenoid.

4. 4

   Verify the Component

   Perform the resistance test (6.0 - 6.8 ohms) directly on the solenoid pins.

5. 5

   Replace or Repair

   If the solenoid fails the resistance test, remove the retaining bolt/nut, slide the old solenoid off the valve stem, and install a replacement solenoid. If the solenoid passes the test, the short circuit is in the wiring harness. Repair any damaged wires between the UCM and the solenoid, ensuring all splices are sealed against moisture.

6. 6

   Reassemble

   Reconnect the wiring harness to the solenoid.

7. 7

   Restore Power and Test

   Reconnect the negative battery cable. Turn the key on, clear the stored UCM fault codes, and test the rear PTO engagement to verify the short circuit has been resolved.