John Deere 000174.04 – ECU: Fuel Temperature Input Voltage Problem

The Engine Control Unit (ECU) has detected an abnormally low voltage from the fuel temperature sensor, indicating the signal is below the expected range. The ECU relies on this sensor to measure fuel temperature to optimize fuel injection timing and quantity for efficient engine operation and emissions control. A low signal voltage typically points to a short circuit in the wiring, a faulty sensor, or an issue with the ECU itself. This fault can cause poor fuel economy, rough idling, engine misfires, and an illuminated check engine light.

• 4555
• 4560
• 4755
• 4760
• 4955
• 4960
• 5045E
• 5055E
• 5065E
• 5075E
• 5075M
• 5085E
• 5085M
• 5090M
• 5090R
• 5100E
• 5100M
• 5100R
• 5115M
• 5115R
• 5125R
• 6105D
• 6105E
• 6105M
• 6105R
• 6110M
• 6110R
• 6115D
• 6115M
• 6115R
• 6120E
• 6120M
• 6120R
• 6125M
• 6125R
• 6130D
• 6130M
• 6130R
• 6135E
• 6135M
• 6135R
• 6140D
• 6140M
• 6140R
• 6145M
• 6145R
• 6150M
• 6150R
• 6155M
• 6155R
• 6170M
• 6170R
• 6175M
• 6175R
• 6190R
• 6195M
• 6195R
• 6210R
• 6215R
• 6230R
• 6250R
• 6610
• 6710
• 6810
• 6910
• 7610
• 7710
• 7810
• 7200R
• 7210R
• 7215R
• 7230R
• 7250R
• 7260R
• 7270R
• 7280R
• 7290R
• 7310R
• 7630
• 7730
• 7830
• 7930
• 8100
• 8100T
• 8110
• 8110T
• 8200
• 8200T
• 8210
• 8210T
• 8300
• 8300T
• 8310
• 8310T
• 8400
• 8400T
• 8410
• 8410T
• 8235R
• 8245R
• 8260R
• 8270R
• 8285R
• 8295R
• 8310R
• 8320R
• 8335R
• 8345R
• 8360R
• 8370R
• 8400R
• 8560
• 8570
• 8760
• 8770
• 8870
• 8960
• 8970
• 9100
• 9200
• 9300
• 9400
• 9230
• 9330
• 9430
• 9530
• 9630
• 9370R
• 9410R
• 9420R
• 9460R
• 9470R
• 9510R
• 9520R
• 9560R
• 6M Series
• 6R Series
• 7R Series
• 8R Series
• 9R Series
• 2264
• 2266
• 9500
• 9510
• 9600
• 9610
• 9650 STS
• 9750 STS
• 9780
• CTS
• CTS II
• 6650
• 6750
• 6850
• 6950
• 290GLC
• 644H
• 670C
• 710K
• 850J

1. 1

   Visually inspect the wiring harness and connector at the fuel temperature sensor (often located at the base of the fuel filter or fuel manifold) for chafing, breaks, corrosion, or loose connections

2. 2

   Scan for any other active fault codes that may indicate a more systemic electrical issue

3. 3

   Perform a continuity test on the wiring between the sensor connector and the ECU connector to check for breaks

4. 4

   Perform a voltage test with the key on, engine off, and sensor disconnected to verify a 5-volt reference voltage at the sensor's electrical connector

5. 5

   Measure the fuel temperature sensor's resistance with a multimeter (typically 0 to 700 ohms, varying with temperature). Infinite resistance (open circuit) or zero resistance (short circuit) indicates a faulty sensor

1. 1

   Relieve fuel pressure

   Ensure the engine is off and cool. Disconnect the fuel pump fuse and run the engine until it stalls to relieve fuel system pressure.

2. 2

   Locate and remove sensor

   Locate the fuel temperature sensor near the fuel filter housing or fuel rail/manifold (e.g., below and behind the EGR cooler outlet pipe on a 6068HT073 engine). Disconnect the electrical connector, place a drain pan underneath, and use a wrench (often 22mm) to remove the old sensor.

3. 3

   Install new sensor

   Apply a small amount of thread sealant to the new sensor's threads if required. Install and tighten to the manufacturer's specified torque.

4. 4

   Reconnect and prime system

   Reconnect the electrical connector, re-install the fuel pump fuse, and prime the fuel system if necessary.

5. 5

   Clear codes and verify

   Start the engine, use a diagnostic tool to clear the fault code, and operate the machine to ensure the code does not return.