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

The control module is receiving a voltage signal from the hydraulic oil temperature sensor circuit that has dropped below the minimum acceptable threshold. This is typically caused by the sensor's signal wire rubbing against the chassis and shorting directly to ground, a damaged connector, or an internal short within the sensor itself.

• TJ Series
• T9000 Series
• T8040
• TG Series
• CR9090
• CX8080 Elevation
• CX8090 Elevation
• Magnum
• Steiger
• MX/TG Series

1. 1

   Inspect the wire harness connection at the hydraulic oil temperature sensor for damaged wires, chafing against the chassis, or terminal back-out inside the connector.

2. 2

   Perform a harness short-to-ground test: Disconnect the wire harness from both the sensor and the INST controller. Check for continuity between the sensor's signal wire and a known good chassis ground. If continuity exists, repair the shorted wiring.

3. 3

   Perform a sensor resistance test: With the sensor disconnected, measure resistance across its terminals. Compare to OEM specs (e.g., 2.21 - 2.69 K ohms at 20°C / 68°F). A reading of 0 ohms indicates an internal short and requires sensor replacement.

1. 1

   Safety First

   Park the machine on a level surface, engage the parking brake, turn off the engine, and remove the key. Allow the hydraulic oil to cool completely to prevent severe burns.

2. 2

   Locate the Sensor

   Locate the hydraulic oil temperature sensor. Depending on the machine, it is typically mounted on the hydraulic reservoir, the tandem pump, or the main hydraulic valve block.

3. 3

   Prepare for Fluid Loss

   Place a clean catch pan underneath the sensor area to catch any hydraulic fluid that escapes during removal.

4. 4

   Remove the Sensor

   Unplug the electrical connector. Use a wrench to carefully unthread and remove the faulty hydraulic oil temperature sensor.

5. 5

   Install the New Sensor

   Thread the replacement sensor into the port and tighten it to the OEM torque specification.

6. 6

   Reconnect and Verify

   Reconnect the electrical harness. Turn the machine's key to the ON position and check the instrumentation panel to ensure the INST 13031 code is no longer active. Clear the stored fault codes.

7. 7

   Fluid Check

   Top off the hydraulic fluid reservoir to replace any oil lost during the procedure.