Case IH 2741 (1044.06) - DEC – DEC: DEC: Hydro solenoid - LSD short to HSD

The fault indicates a short circuit in the control wiring or the coil of the Hydro Solenoid. The controller has detected that the power supply wire (HSD) and the ground return wire (LSD) are touching (shorted together), or the solenoid coil itself has suffered an internal short circuit. This causes the electrical current to bypass the normal resistance of the solenoid coil, which will disable the hydrostatic drive function to protect the controller from excessive current draw.

• VESTRUM CVX
• Case IH CVX / CVXDrive Tractors (e.g., Puma 165-225 CVX, Maxxum CVX)
• Case IH Axial-Flow Combines

1. 1

   Visual Inspection: Inspect the wiring harness leading to the transmission/hydrostatic pump block. Look for pinched wires, melted insulation, or areas where the harness rubs against the chassis or transmission housing.

2. 2

   Solenoid Coil Resistance Test: Disconnect the electrical connector at the Hydro Solenoid and measure the resistance across the two pins. If the reading is near 0.0 Ohms, the solenoid coil is internally shorted (a healthy solenoid typically reads 5 to 15 Ohms).

3. 3

   Harness Short Test: With the solenoid disconnected and key OFF, disconnect the harness at the DEC module. Measure for continuity between the HSD (power) pin and the LSD (ground) pin on the harness side to check if wires are shorted together.

1. 1

   Turn off battery

   If the harness is shorted: Turn the battery disconnect switch to the OFF position.

2. 2

   Trace harness

   Trace the harness from the hydro solenoid back to the DEC to locate the chafe point.

3. 3

   Cut damaged wires

   Cut out the damaged section of the HSD and LSD wires.

4. 4

   Splice new wire

   Splice in new wire using weather-sealed, heat-shrink butt connectors.

5. 5

   Wrap and secure harness

   Wrap the repaired section in high-temperature split loom and secure it with zip ties away from vibration points.

6. 6

   Clean area

   If the Hydro Solenoid is internally shorted: Clean the area around the hydrostatic pump/transmission block to prevent dirt from entering the hydraulic system.

7. 7

   Disconnect connector

   Disconnect the electrical connector from the solenoid.

8. 8

   Remove retaining nut

   Remove the retaining nut at the end of the solenoid stem.

9. 9

   Remove faulty coil

   Slide the faulty solenoid coil off the valve cartridge. (Note: If it is a one-piece cartridge valve, you will need to unthread the entire valve from the block. Have a catch pan ready for hydraulic fluid).

10. 10

    Install new coil

    Slide the new solenoid coil onto the stem and install the retaining nut (do not over-tighten, as this can distort the coil).

11. 11

    Reconnect connector

    Reconnect the electrical connector.

12. 12

    Test functionality

    Turn the battery switch ON, clear the fault codes via the cab display or diagnostic tool, and test the ground drive functionality.