Massey Ferguson 174.03 – Engine Control Unit (ECU) / EEM: Fuel Temperature Sensor High Voltage

The Engine Control Unit is receiving a signal from the fuel temperature sensor that is above the normal operating range (typically exceeding 4.9 volts). This indicates an open circuit in the sensor's wiring harness, a short to a power source, or an internal sensor failure, which triggers a warning lamp and reduces engine power (Degradation Level 1).

• 4710
• 7724S
• 5712SL
• Interim Tier 4 (2012-2015)
• 7722
• 7722S
• 7615
• 5613
• 5713SL
• 7720S
• 7716
• 7718
• T4
• 7715
• 5710SL
• 7726
• 7616
• 7618
• 5608
• 4708
• 7619
• 7626
• 7726S
• 7624
• 4707
• 4709
• 5711SL
• 7614
• 7718S
• 5610
• 7620
• 7719
• 7714
• 7716S
• T4 (2015-2021)
• 5612
• 7622
• 7720
• Tier 4 (2015-2021)
• 5611
• 7715S
• 5609
• 7724

1. 1

   Visually inspect the fuel temperature sensor and its electrical connector for backed-out pins, corrosion, moisture, or physical damage.

2. 2

   Trace the wiring harness from the sensor back to the ECU, looking for chafed wires shorting to a power source or broken wires causing an open circuit.

3. 3

   Using a multimeter, disconnect the sensor and check the sensor signal wire for a short to voltage.

4. 4

   Check the continuity of the signal and ground wires between the sensor connector and the ECU pins.

5. 5

   If the wiring tests good (no open circuits or shorts to power), the fault is highly likely an internal open circuit within the fuel temperature sensor itself.

1. 1

   Turn off the tractor, remove the key, and disconnect the negative battery terminal to prevent electrical spikes.

2. 2

   Locate the fuel temperature sensor on the engine's fuel system (typically near the fuel filter housing or fuel inlet).

3. 3

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

4. 4

   If the diagnostic checks pointed to a wiring issue, repair the broken wire or replace the damaged pigtail connector.

5. 5

   If the sensor is deemed faulty, use a wrench to carefully unthread the old sensor from the fuel line/housing. Have a rag ready to catch any minor fuel spillage.

6. 6

   Install the new fuel temperature sensor. Thread it in by hand to prevent cross-threading, then tighten it to the OEM torque specification.

7. 7

   Reconnect the electrical harness until it clicks into place.

8. 8

   Reconnect the battery, turn the key to the ON position, and use a diagnostic scan tool to clear the 000174.03 fault code.

9. 9

   Start the engine and verify that the code does not return and that the engine is no longer in a derated power state.