Case IH 2552 – Universal Control Module (UCM): Transmission oil pressure too high

This condition is triggered when the system detects that the hydraulic pressure within the transmission circuit has exceeded the maximum allowable threshold. This can be a "false" high caused by an electrical failure (such as a faulty sensor or a short circuit in the wiring harness) or a true mechanical high pressure caused by a stuck relief valve or a blocked hydraulic circuit.

• Optum
• Case IH Puma Series: 130, 150, 165, 180, 195, 210, 225 CVX
• Case IH Magnum MX Series: 215, 245, 275, 305

1. 1

   Check for Companion Codes: Scan the UCM for any other active error codes. If other codes are present (especially voltage or CAN bus codes), diagnose those first, as they may be causing a false reading.

2. 2

   Fluid and Filter Inspection: Inspect the transmission oil color and smell. Change the hydraulic filters and cut the old ones open to inspect for metal debris or heavy contamination.

3. 3

   Manual Pressure Test: Perform a manual pressure test on the transmission hydraulic circuit (both hot and cold) using a mechanical gauge. This is critical to prove whether the pressure is actually high (mechanical issue) or if the sensor is lying (electrical issue).

4. 4

   Electrical Testing (If mechanical pressure is normal): Test the transmission oil pressure sensor (X-273) and its wiring harness. Check for a short to voltage or a faulty UCM connection.

5. 5

   Valve Behavior (If mechanical pressure is genuinely high): Check the behavior of the pressure relief valves and solenoids, which may be sticking due to debris.

1. 1

   Verify the Baseline

   Connect a diagnostic scan tool, record the fault history, and clear the code to see if it immediately returns upon startup.

2. 2

   Isolate the Sensor (X-273)

   Locate the transmission oil pressure sensor (X-273) on the transmission housing. Disconnect the wiring harness and inspect the pins for corrosion, moisture, or damage.

3. 3

   Test the Harness

   Use a multimeter to check the wiring harness between the sensor connector and the UCM for continuity and ensure there is no short circuit to the 5V/12V reference or ground.

4. 4

   Replace the Sensor

   If the wiring is intact and the mechanical pressure test proved the actual transmission pressure is within spec, the X-273 sensor has failed. Unscrew the old sensor, apply a dab of thread sealant to the new sensor, and install it.

5. 5

   Address Mechanical Overpressure (If Applicable)

   If the mechanical gauge confirmed the pressure is actually too high, the hydraulic circuit is at fault. You must drop the transmission valve block, disassemble the pressure relief valves, and clean out any debris or replace sticking spool valves.

6. 6

   Reassembly and Calibration

   Reconnect all components, refill the system with clean OEM transmission fluid, clear the error code via the UCM, and test the tractor under load to ensure normal operation.