Case IH 2580 – FRC / UCM / CAB: Left brake pressure transducer - open circuit / short to ground

The control module is not receiving the expected variable voltage signal from the left brake pressure transducer, indicating an open circuit (break in wiring, disconnected plug, failed internal sensor) or short to ground (signal wire chafed touching chassis, or sensor failed internally).

• Optum
• Case IH Magnum 180
• Case IH Magnum 190
• Case IH Magnum 210
• Case IH Magnum 225
• Case IH Magnum 250
• Case IH Magnum 280
• Case IH Magnum 310
• Case IH Magnum 340
• Case IH Magnum 380
• Case IH Magnum Rowtrac
• Case IH Puma 165
• Case IH Puma 180
• Case IH Puma 195
• Case IH Puma 210
• Case IH Puma 225

1. 1

   Visually inspect the left brake pressure transducer connector (e.g., X-549 or X-461) and the corresponding ECU/UCM connector. Ensure they are fully seated, undamaged, and pins are tight and free of corrosion.

2. 2

   Perform a voltage supply test: Disconnect the transducer connector, turn the ignition ON, and measure the voltage at the supply pin on the harness side (should read a steady +5 Volts reference from the ECU).

3. 3

   Verify ground continuity between the ground pin on the harness connector and the tractor chassis.

4. 4

   Test the signal wire for continuity from the sensor connector back to the FRC/UCM pin.

5. 5

   Test the signal wire for a short to ground. If there is continuity to ground while both ends are unplugged, the harness is shorted.

1. 1

   Prepare machine

   Park the tractor on a level surface, engage the parking brake, turn off the engine, and remove the key.

2. 2

   Relieve system pressure

   Depress the brake pedals several times to relieve any residual hydraulic or pneumatic pressure in the braking system.

3. 3

   Locate and disconnect transducer

   Locate the left brake pressure transducer (typically mounted on the brake control valve block or near the transmission housing). Release the locking tab (Wedge Lock) and disconnect the electrical connector.

4. 4

   Repair wiring harness

   If diagnostic checks revealed a wiring issue (open circuit or short to ground), repair the chafed wire or replace the damaged harness section.

5. 5

   Remove faulty transducer

   If the wiring tested good, the transducer has failed internally. Use a wrench to unthread and remove the faulty brake pressure transducer. Have a rag ready to catch any minor fluid drips.

6. 6

   Install new transducer

   Install the new OEM brake pressure transducer. Torque the sensor to the specification for steel hydraulic fittings of its thread size (typically 11 to 22 Nm / 96 to 192 lb-in). Do not overtighten.

7. 7

   Reconnect and test

   Reconnect the electrical connector, ensuring the secondary locking tab clicks into place. Start the tractor, apply the brakes firmly several times, and inspect the sensor fitting for any hydraulic or air leaks.

8. 8

   Clear fault codes

   Use the AFS Pro display or a diagnostic service tool to clear the inactive fault codes.