Case IH 2826 – Transmission Control Module (TCU) or Vehicle/Hydraulic Controller: Hydraulic oil temperature sensor shorted to ground

The controller is seeing a voltage signal near 0 volts, indicating that the sensor's signal wire is shorted directly to the chassis ground or the sensor has failed internally.

• Steiger T4B
• Case IH STX Steiger Series
• Case IH Magnum Series
• Case IH AFX Series Combines

1. 1

   Check the Display: Enter the Universal Display Plus 'DIAG' screen (if equipped). Select the 'HYDRAULIC' menu, and select 'RES TEMP SEN' to check the live voltage range. A reading below 0.5V confirms the short to ground.

2. 2

   Inspect the Harness: Visually inspect the wiring harness between the hydraulic oil temperature sensor and the ECU. Look for chafed wires, melted insulation, or areas where the wire might be rubbing against the chassis.

3. 3

   Connector Check: Ensure the connectors are fully seated, not damaged, and that the pins are in the correct position with a tight fit.

4. 4

   Disconnect Test: Disconnect the sensor. If the fault code changes from 2826 (Short to Ground) to 2825 (Open Circuit), the wiring harness is likely intact, and the sensor itself has an internal short and must be replaced.

1. 1

   Turn off the machine, engage the parking brake, and disconnect the battery ground cable to protect the ECU.

2. 2

   Locate the hydraulic oil temperature sensor.

   Depending on the model, it is typically threaded into the hydraulic oil reservoir tank (e.g., sensor B-18 on AFX combines) or the hydraulic filter housing.

3. 3

   Disconnect the electrical harness connector from the sensor.

4. 4

   Thoroughly clean the area around the sensor port to prevent dirt and debris from contaminating the hydraulic system.

5. 5

   Place a catch pan beneath the sensor location to catch any residual hydraulic fluid.

6. 6

   Unthread the faulty sensor using a wrench and remove it.

7. 7

   Install the new sensor and tighten to the manufacturer's torque specification.

   Ensure any required O-rings or sealing washers are in place.

8. 8

   Reconnect the electrical harness connector.

9. 9

   Reconnect the battery, turn the ignition on, and clear the inactive fault code.

   Use the Electronic Service Tool (EST) or the in-cab diagnostic display to clear the inactive fault code.

10. 10

    Run the machine to bring the hydraulic fluid up to operating temperature and verify that the code does not return and there are no fluid leaks.