Case IH F-175-20 - ECU – Engine Control Unit (ECU): Engine Oil Temperature Sensor Signal Not Plausible

The system has detected that the engine oil temperature data derived from the sensor is above the maximum limit or is irrational compared to other engine operating parameters (plausibility error).

• MAGNUM AFS Connect
• Puma
• Magnum
• Steiger
• Axial-Flow combines

1. 1

   Verify operating conditions to ensure the machine was not subjected to extreme engine misuse (e.g., running at maximum load with blocked cooling systems or closed cowl flaps).

2. 2

   Verify that the engine oil is at the correct level and is not degraded.

3. 3

   Check the engine oil cooler and radiator matrix for heavy soiling, debris blockage, or restricted airflow.

4. 4

   Inspect the wiring harness leading to the engine oil temperature sensor for chafing, short circuits to ground, short circuits to battery voltage, or open circuits.

5. 5

   Test the sensor's resistance with a multimeter to see if it matches the expected values for the ambient temperature. If the reading is implausible (e.g., engine is cold but sensor reads hot), the sensor is likely defective.

1. 1

   Cool down engine

   Allow the engine and oil to cool down completely to avoid burn hazards.

2. 2

   Clean cooling package

   If the diagnostic check revealed a blocked oil cooler, thoroughly blow out the cooler and radiator fins with compressed air or wash them out.

3. 3

   Repair wiring

   If harness damage was found during the diagnostic phase, repair the broken wires or replace the sensor pigtail connector.

4. 4

   Replace the sensor

   If the wiring is intact but the sensor failed the accuracy test: Locate the engine oil temperature sensor on the engine block/oil filter housing. Disconnect the electrical connector, place a catch pan underneath, unthread the old sensor and install the new OEM sensor. Torque to the manufacturer's specification and reconnect the harness.

5. 5

   Clear codes

   Turn the battery disconnect switch on, cycle the key, and use a diagnostic scan tool (or the tractor's AFS Pro display) to clear the inactive fault codes. Run the engine to verify the code does not return.