Case IH 2557 – UCM (Universal Control Module) or CCU (Central Control Unit): Hydro 1 solenoid - open circuit or short circuit to ground

The control module has detected a break in the electrical circuit (open circuit) or a wire that is inappropriately touching the chassis/ground (short circuit to ground) on the circuit controlling the Transmission Hydrostat 1 Solenoid.

• Optum
• Case IH Puma Series (Puma 130 CVX, 165, 180, 195, 210, 225 CVX)
• Case IH Magnum Series (Magnum 210, 220 CVT)

1. 1

   Check external power supply and charging system for faults

2. 2

   Inspect the Hydrostat 1 solenoid connector (X-544 or X-645), intermediate wire harness connector (X-020), and UCM connector (X-955)

3. 3

   Verify pin fitment to ensure all connectors are fully seated, undamaged, and pins are in the correct position with a tight fit

4. 4

   Test the solenoid by disconnecting it and using a multimeter to check internal resistance and continuity to ground (to verify if it has shorted out)

5. 5

   Test the wiring harness for continuity between the solenoid connector and the UCM to rule out a broken wire or a wire rubbing against the tractor frame

6. 6

   Check for a faulty UCM/CCU

1. 1

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

2. 2

   Locate the Hydro 1 solenoid.

   Depending on your specific model, it is typically located either in the bell housing or inside the transmission side cover.

3. 3

   Repair or replace the affected harness section.

   Perform this if the diagnostic checks revealed damaged wiring or corroded connector pins.

4. 4

   Remove the retaining hardware and extract the faulty Hydro 1 solenoid.

   Perform this if the wiring is intact but the solenoid failed the multimeter test.

5. 5

   Install the new Transmission Hydrostat Control Solenoid and securely reconnect the wiring harness.

6. 6

   Reconnect the battery.

7. 7

   Use a diagnostic tool to clear the error code from the UCM/CCU.

   Test the system for normal operation to ensure the code does not return.