New Holland 3015 – ECU: Fuel Temperature Signal - Signal Above Range Max

The Engine Control Unit (ECU) has detected that the signal voltage from the fuel temperature sensor exceeds the maximum specified limit. This 'Signal Above Range Max' condition typically indicates an open circuit or a short circuit to a positive voltage source in the sensor's wiring. Because the fuel temperature sensor is a negative temperature coefficient (NTC) thermistor, an abnormally high voltage signal causes the ECU to incorrectly read the fuel as extremely cold (high resistance). This false reading can lead to improper fuel injection timing and quantity, resulting in hard starting, poor engine performance, and reduced fuel economy.

• T6020
• T6030
• T6050
• T6070
• T8010
• T8020
• T8030
• T8040
• T8050
• TG215
• TG245
• TG275
• TG305
• Magnum 215
• Magnum 245
• Magnum 275
• Magnum 305
• Magnum 335
• MX215
• MX245
• MX275
• MX305
• 2377
• 2388
• 2577
• 2588
• 5088
• 6088
• 7088

1. 1

   Locate the fuel temperature sensor (commonly on the fuel filter head, high-pressure pump, or fuel line) and visually inspect the wiring harness for chafing, melting, or corrosion.

2. 2

   Check the sensor connector to ensure it is securely fastened and the pins are clean and free of contamination.

3. 3

   Check for an open circuit by disconnecting the sensor, turning the ignition ON (engine off), and verifying a 5-volt reference supply from the ECU at the harness connector. If 5 volts are not present, there is an issue with the wiring back to the ECU or the ECU itself.

4. 4

   Verify continuity of the ground wire from the sensor connector to the chassis ground (should be near 0 ohms).

5. 5

   Test the sensor's internal resistance with a multimeter; if it reads infinite resistance (open loop), the sensor has failed.

6. 6

   Check for a short to power by measuring voltage between the signal wire pin at the harness and chassis ground (should be near 5V; if 12V, there is a short to another power source in the harness).

1. 1

   Disconnect battery

   Disconnect the negative battery terminal to prevent electrical damage before starting repairs.

2. 2

   Relieve fuel pressure

   If working on the high-pressure side of the fuel system, follow the manufacturer's procedure to safely relieve any residual pressure.

3. 3

   Remove faulty sensor

   Place a drain pan under the sensor location to catch spilled fuel. Disconnect the electrical connector and carefully unscrew the sensor.

4. 4

   Install new sensor

   Ensure the sealing surface is clean. Lightly lubricate the O-ring on the new sensor with clean diesel fuel or engine oil, and tighten to the manufacturer's specified torque.

5. 5

   Reconnect and prime

   Reconnect the electrical connector and the battery. If the fuel system was opened, prime the system according to the operator manual to remove any air.

6. 6

   Clear fault codes

   Turn the ignition on and use the instrument cluster or a diagnostic tool to clear the active fault code.

7. 7

   Verify the repair

   Start the engine and let it run. Check for any fuel leaks and ensure the fault code does not reappear.