Case IH 4731 – UCM (Universal Control Module): Right Swash Plate Angle Sensor Pin A Open Or Shorted To Ground

The control module has detected that the electrical signal coming from Pin A of the right swash plate angle sensor is either completely interrupted (an open circuit, such as a broken wire or disconnected plug) or is shorting directly to a ground source (0V).

• skid steer
• Skid Steer Loaders (SSL) (SR130, SR150, SR175, SR200, SR220, SR250, SV185, SV250)
• Compact Track Loaders (CTL)
• Case IH tractors equipped with CVT/hydrostatic drive components

1. 1

   Check for stacking codes (such as 4754) which highly indicate a wiring harness issue rather than a sensor failure.

2. 2

   Locate the swash plate angle sensor on the bottom of the hydrostatic travel pumps by following the hydraulic hoses from the right travel motor.

3. 3

   Visually inspect the sensor for physical damage such as being bumped, cracked, or crushed by debris.

4. 4

   Disconnect the sensor and inspect the connector for water intrusion, bent pins, or corrosion. Trace the wiring harness back to the UCM to check for pinched, cut, or chafed wires.

5. 5

   Test Pin A on the machine-side harness for continuity to ground using a multimeter. Continuity to ground while unplugged indicates a shorted harness; if the harness tests fine, the sensor's internal circuitry has failed.

1. 1

   Power Down

   Turn off the machine, remove the key, and disconnect the negative battery cable to prevent electrical spikes to the UCM during repair.

2. 2

   Access the Pump

   Gain access to the hydrostatic pumps (usually requires lifting the cab or opening the rear/belly access panels depending on the SSL/CTL model).

3. 3

   Remove the Sensor

   Disconnect the electrical pigtail from the right swash plate angle sensor. Remove the mounting screws holding the sensor to the bottom of the travel pump.

4. 4

   Install the New Sensor

   Mount the new swash plate angle sensor to the pump. (Note: OEM documentation notes that mounting screws are often "NSS" - Not Serviced Separately - so you will need to reuse the original screws or procure them locally).

5. 5

   Reconnect

   Plug the wiring harness back into the sensor, ensuring the locking tab clicks into place.

6. 6

   Restore Power and Clear Codes

   Reconnect the battery. Turn the key to the ON position and use the machine's display or the Case IH Electronic Service Tool (EST) to clear the inactive 4731 fault code.

7. 7

   Test Operation

   Start the machine and test the right-side drive functions to ensure smooth operation and verify the code does not return.