Case IH 3459 (F-175-15) - ECU – Engine Control Unit (ECU): Engine oil temperature too high

This code triggers when the engine control system detects that the engine oil temperature has exceeded the maximum safe operating threshold, which typically triggers an audible warning, flashes a red warning lamp, and forces the engine into a derated state.

• VESTRUM CVX
• Farmall
• Maxxum
• combines
• wheel loaders

1. 1

   Verify Actual Temperature: Use a diagnostic scan tool to monitor live data parameters (specifically Engine Oil Temperature). Compare this reading against a manual temperature probe on the oil pan to confirm if the engine is genuinely overheating or if the sensor is reading falsely.

2. 2

   Inspect the Sensor Circuit: Check the wiring harness between the Engine Oil Temperature sensor and the ECU for chafing, shorts, or breaks.

3. 3

   Inspect Connectors: Disconnect the sensor and inspect the 2-pin connector for corrosion, moisture, or backed-out pins.

1. 1

   Cool engine

   Turn off the tractor and allow the engine to cool completely to avoid burns from hot oil.

2. 2

   Locate sensor

   Locate the engine oil temperature sensor on the engine block (refer to your specific engine's service manual diagram, such as the NEF engine layout).

3. 3

   Disconnect wiring

   Disconnect the engine wiring cable from the sensor's 2-pin rectangular connector.

4. 4

   Remove faulty sensor

   Using a 19mm or 22mm wrench (depending on the specific OEM/aftermarket casting), unbolt and remove the faulty sensor. Have a rag ready to catch any minor oil seepage.

5. 5

   Install new sensor

   Install the new engine oil temperature sensor. Ensure the new gasket/seal is in place. The thread pitch is M12x1.5.

6. 6

   Reconnect wiring

   Reconnect the electrical connector until it clicks securely.

7. 7

   Clear fault codes

   Turn the ignition key to the 'Accessory' position and use your diagnostic scan tool (or the onboard monitor's service menu) to clear the active fault codes.

8. 8

   Verify repair

   Start the engine, check for oil leaks around the new sensor, and verify that the warning lamps remain off and the engine is no longer derated.