Case IH 13031 – INST or INST2: Hydraulic Oil Temperature sensor voltage is too low (short to ground)

The controller is receiving a voltage signal from the hydraulic oil temperature sensor that falls below the acceptable minimum threshold, typically caused by the sensor's signal wire shorting directly to a ground source or an internal short within the sensor itself.

• MX Magnum
• STX Steiger
• MX Magnum Series
• TG Series
• Steiger Series
• Puma Series
• AFX Combine Series

1. 1

   Inspect the wiring harness leading to the hydraulic oil temperature sensor for chafed insulation, pinched wires against the chassis, or melted wire loom.

2. 2

   Unplug the sensor and inspect the connector pins for corrosion, moisture, or damage that could bridge the terminals.

3. 3

   Perform a Sensor vs. Harness Isolation Test: Disconnect the sensor, turn the key on, and check active fault codes. If the code changes to 13032, the sensor is internally shorted. If it remains 13031, the short to ground is in the wiring harness.

1. 1

   Repair wiring harness

   If the wiring harness is at fault: Trace the signal wire from the sensor back to the INST controller. Locate the shorted section of the wire, cut out the damaged section, splice in a new wire using weather-sealed heat-shrink butt connectors, and re-loom the harness.

2. 2

   Prepare machine for sensor replacement

   If the sensor is at fault: Turn off the machine, relieve any residual hydraulic pressure, and disconnect the battery.

3. 3

   Locate and clean sensor area

   Locate the hydraulic oil temperature sensor (commonly located on the PFC pump inlet manifold or directly on the hydraulic reservoir tank). Clean the area around the sensor to prevent dirt from entering the hydraulic system.

4. 4

   Prepare for fluid loss

   Place a catch pan underneath the sensor area. Depending on the sensor's location relative to the fluid level, you may need to drain some hydraulic fluid first, or work quickly to swap the sensor and minimize fluid loss.

5. 5

   Replace sensor

   Unscrew the faulty sensor. Thread in the new replacement sensor and tighten to OEM torque specifications.

6. 6

   Reassemble and verify

   Reconnect the electrical harness. Top off the hydraulic fluid if any was lost. Reconnect the battery, turn the key on, and verify that code 13031 has cleared.