Case IH 2592 (519167.17) - DEC – Transmission Control Unit (TCU): Reverse Clutch Pressure Sensor Signal lower than expected

The signal voltage from the Reverse Clutch Pressure Sensor is 'Out of Range Low' or lower than the expected minimum threshold. This indicates the sensor has failed internally, the wiring harness is disconnected/open/shorted, or there is a severe internal hydraulic leak preventing the reverse clutch from building adequate pressure.

• MAXXUM T4E
• Magnum 235
• Magnum 260
• Magnum 275
• Magnum 290
• Magnum 315
• Magnum 340
• Magnum 370
• Maxxum
• Farmall
• Puma

1. 1

   Visually inspect the reverse clutch pressure sensor on the transmission control valve block (left side of clutch housing) for pushed-out pins, corrosion, or a disconnected harness.

2. 2

   Verify the sensor is receiving a 5V reference supply voltage from the TCU.

3. 3

   Verify the ground circuit has good continuity back to the control unit.

4. 4

   Check the signal wire for an open circuit or a short to ground.

5. 5

   Perform a hydraulic pressure test to rule out mechanical failure: install a manual hydraulic pressure gauge into the reverse clutch diagnostic test port. Start the engine, command reverse, and verify mechanical pressure reaches the specified minimum (e.g., ~297 PSI / 20.5 bar at 2200 RPM). If mechanical pressure is good but the sensor reads low, the sensor is faulty.

1. 1

   Preparation

   Park the tractor on a level surface, engage the parking brake, turn off the engine, and allow the transmission oil to cool.

2. 2

   Access the Sensor

   Locate the reverse clutch pressure sensor on the transmission valve body. Clean the area around the sensor to prevent dirt from entering the hydraulic system.

3. 3

   Removal

   Disconnect the 3-pin electrical connector. Using the appropriate wrench, unthread the pressure sensor from the transmission port. Have a shop rag ready to catch a small amount of residual transmission fluid.

4. 4

   Installation

   Thread the new pressure sensor into the port and tighten to the OEM torque specification.

5. 5

   Reconnection

   Reconnect the electrical harness, ensuring the locking tab clicks into place.

6. 6

   Calibration & Clearing

   Turn the key on. Use the tractor's diagnostic display or a service tool (like the CNH EASy tool) to clear the inactive fault code.

7. 7

   Validation

   Start the tractor, bring the transmission fluid up to operating temperature, and perform a transmission clutch calibration. Shift from neutral to reverse to ensure the code does not return and the clutch engages smoothly.