Case IH F-174-00 - ECU – Engine Control Unit (ECU): Fuel temperature sensor voltage is higher than expected.

The Engine Control Unit (ECU) is reading a voltage on the fuel temperature sensor signal circuit that exceeds the normal operating range. Because temperature sensors are typically NTC thermistors, a high voltage reading usually indicates high resistance, pointing to an open circuit, a disconnected sensor, a broken wire, or a short to a voltage source.

• MAGNUM AFS Connect
• Magnum 250-380
• Magnum 400 AFS Connect
• Puma 125 through 200
• Puma CVX
• Maxxum 100 through 150
• 240 Series Axial-Flow Combines
• Austoft 9900 Sugarcane Harvesters
• 580N Backhoes
• 570NXT Backhoes
• SV250 Skid Steers
• SV300 Skid Steers
• 721F Wheel Loaders
• 921G Wheel Loaders

1. 1

   Visually inspect the fuel temperature sensor connector (located on or near the fuel filter housing) for disconnected, loose, bent, or corroded pins.

2. 2

   Inspect the wiring harness between the sensor and the Engine ECU for any signs of chafing, breaks (which would cause an open circuit), or a short to battery voltage.

3. 3

   Disconnect the sensor and measure its resistance with a multimeter. The resistance should change according to ambient temperature. An infinite reading indicates the sensor has failed internally.

4. 4

   With the key ON and the sensor disconnected, check the ECU reference voltage and ground at the harness connector to ensure the ECU is supplying the correct signal.

1. 1

   Cool down engine

   Turn off the machine, remove the key, and allow the engine to cool down completely.

2. 2

   Locate sensor

   Locate the fuel temperature sensor on the engine block or fuel filter housing.

3. 3

   Disconnect harness

   Disconnect the electrical harness connector from the sensor.

4. 4

   Clean area

   Clean the area around the sensor thoroughly to prevent dirt or debris from entering the fuel system.

5. 5

   Remove faulty sensor

   Unscrew and remove the faulty fuel temperature sensor. Have a shop rag ready to catch any minor fuel spillage.

6. 6

   Install new sensor

   Install the new sensor, ensuring the sealing ring/O-ring is properly seated. Tighten to the manufacturer's specified torque.

7. 7

   Reconnect harness

   Reconnect the electrical harness connector until it clicks securely into place.

8. 8

   Clear fault code

   Turn the key to the ON position and use a diagnostic scan tool to clear the F-174-00 / 3015 fault code.

9. 9

   Verify repair

   Start the engine and inspect the sensor area for any fuel leaks. Verify that the fault code does not return.