Case IH 5503 – UCM or IC: Electro-Hydraulic Aux Output Shorted To Power

The machine's controller has detected that the electrical circuit responsible for commanding the Electro-Hydraulic (EH) Auxiliary output valve is receiving unexpected voltage (shorted to a 12V power source). This prevents the controller from properly modulating the auxiliary hydraulics, as the circuit is bypassing the normal electrical load or receiving power when it is not being commanded.

• skid steer
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• SR series
• SV series
• TR series
• TV series
• SR175
• TV380
• TR340
• Tractors
• Magnum series
• Puma series
• Maxxum series

1. 1

   Visually inspect the wiring harness running from the UCM/IC to the EH Auxiliary control valve block for pinched wires, melted insulation, or rubbing against the chassis or a 12V power wire.

2. 2

   Perform a voltage check on the harness (harness short cause): Disconnect the electrical connector at the EH Aux solenoid, turn the key ON (engine off), and measure voltage on the signal wire. If it reads 12V while not commanded, the harness is shorted to power.

3. 3

   Perform a resistance check on the solenoid (solenoid short cause): With the solenoid disconnected, measure resistance across the pins of the EH Aux solenoid coil. If resistance is at or near 0 Ohms, the coil is internally shorted.

1. 1

   Disconnect Power

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

2. 2

   Access the Valve Block

   Tilt the cab (for SSL/CTLs) or remove the necessary access panels to reach the main hydraulic control valve block.

3. 3

   Address a Harness Short

   If your diagnostics proved the harness was shorted, trace the wire back from the solenoid to the UCM. Locate the damaged section of the wire. Cut out the damaged wire and splice in a new section using marine-grade, heat-shrink butt connectors to ensure a weather-tight seal.

4. 4

   Replace a Shorted Solenoid

   If applicable, disconnect the wiring harness from the faulty EH Aux solenoid. Remove the retaining nut at the end of the solenoid stem. Slide the old solenoid coil off the valve cartridge. Slide the new OEM solenoid coil onto the stem and torque the retaining nut to OEM spec (do not overtighten, or you will crack the plastic coil housing).

5. 5

   Reassembly

   Reconnect the electrical pigtail to the new solenoid, ensuring the locking tab clicks and the weather seal is seated.

6. 6

   Test

   Reconnect the battery, start the machine, and test the auxiliary hydraulic functions. Verify that the 5503 fault code has moved to "Inactive" or cleared entirely.