Iveco 023A – Engine Control Unit (ECU) / EDC: High Voltage circuit oil temperature sensor

The engine's control module is receiving a voltage signal from the oil temperature sensor that exceeds the maximum allowable threshold. This typically points to an open circuit, a short to battery voltage, or a completely failed sensor with infinite internal resistance.

• Iveco Stralis
• Iveco Eurocargo
• Iveco Daily
• FPT NEF F4

1. 1

   Inspect the wiring harness and the connector at the oil temperature sensor for backed-out pins, corrosion, or chafed wires

2. 2

   With the ignition key ON, disconnect the sensor and probe the harness connector for a short to battery voltage or an open ground circuit

3. 3

   Measure the internal resistance across the pins of the sensor itself (e.g., approx 2.5K Ohms at 20 degrees C). A reading of OL indicates internal failure

4. 4

   Use an infrared laser thermometer on the oil pan or oil cooler to verify the actual physical oil temperature and compare to live data on a diagnostic scan tool to confirm the sensor is reading falsely

1. 1

   Turn off the ignition switch and disconnect the vehicle's battery.

   This prevents electrical shorts.

2. 2

   Locate the engine oil temperature sensor.

   Depending on the engine model, it is typically located on the engine block, the oil filter housing, or the oil pan.

3. 3

   Depress the locking tab and carefully disconnect the electrical harness from the sensor.

4. 4

   Repair the damaged section of the harness or remove the old sensor.

   If the sensor is faulty, use an appropriate deep socket or wrench to remove the old sensor. Have a rag ready, as a small amount of oil may leak.

5. 5

   Clean the mating surface on the engine block or housing.

6. 6

   Install the new sensor.

   Ensure the new sealing washer or O-ring is in place (if applicable) and tighten to the manufacturer's specified torque.

7. 7

   Reconnect the electrical harness.

   Ensure it clicks securely into place.

8. 8

   Reconnect the battery.

9. 9

   Connect a diagnostic scan tool, clear the 023A fault code, and run the engine to verify the repair.