John Deere 000157.02 – ECU: Fuel Rail Pressure Sensor Signal Voltage Out Of Range

The signal voltage from the Fuel Rail Pressure Sensor is outside the expected range as detected by the Engine Control Unit (ECU). The ECU is receiving a voltage signal that is intermittent, unstable, or irrational compared to other engine operational data. This prevents the ECU from accurately determining the pressure within the common rail fuel system, which can adversely affect the proper operation of the engine's fuel system and lead to symptoms such as difficulty starting, rough idling, reduced power, and poor fuel economy.

• 5085E
• 5090E
• 5090EL
• 5100E
• 5085M
• 5100M
• 5100MH
• 5100ML
• 5115ML
• 5090M
• 5115M
• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 8225R
• 8235R
• 8245R
• 8260R
• 8270R
• 8285R
• 8295R
• 8295RT
• 8310R
• 8310RT
• 8320R
• 8320RT
• 8335R
• 8335RT
• 8345R
• 8345RT
• 8360R
• 8360RT
• 8370R
• 8370RT
• 9230
• 9330
• 9430
• 9530
• 9630
• S560
• S650
• S660
• S670
• S670H
• T560
• T660
• T670
• W650
• W660
• R4038
• R4045
• R4060

1. 1

   Visually inspect the wiring harness and connector leading to the fuel rail pressure sensor for damage, chafing, corrosion, pinched wires, or loose connections.

2. 2

   Check for other active fault codes. Codes related to low fuel pressure (e.g., SPN 94.17) could indicate a clogged fuel filter, which should be addressed first.

3. 3

   Perform a Reference Voltage Test: Disconnect the sensor, turn ignition ON (engine off), and measure voltage between the 5V reference pin and ground (should be 4.5-5.0V).

4. 4

   Perform a Ground Circuit Test: Measure resistance between the ground pin on the harness connector and the battery's negative post (should be less than 0.5 ohms).

5. 5

   Perform a Static Signal Voltage Test: Reconnect the sensor, turn ignition ON (engine off), and back-probe the signal wire (should be approximately 0.5V).

6. 6

   Perform a Dynamic Signal Voltage Test: Start the engine. At idle, signal voltage should be 1.2V-1.5V. During snap acceleration, it should climb smoothly to 3.5V-4.0V. If stuck at 0V/5V or unchanging, the sensor has likely failed internally.

1. 1

   Prepare machine for service

   Park the machine on a level surface, stop the engine, remove the key, and disconnect the battery ground strap to disable the electrical system.

2. 2

   Relieve fuel system pressure

   CRITICAL SAFETY STEP: Locate and open the drain valve on the fuel filter or water separator to relieve the extremely high pressure in the common rail system.

3. 3

   Remove the faulty sensor

   Locate the sensor on the common fuel rail (remove covers or components if necessary, potentially requiring the loosening or removal of other parts like the injection pump). Disconnect the electrical connector and carefully unscrew the old sensor.

4. 4

   Install the new sensor

   Clean the mounting surface. Install the new sensor with correctly seated O-rings/seals. Screw in by hand, then tighten to the manufacturer's specified torque. Note: Proper torque is crucial for a correct seal, which is often metal-on-metal.

5. 5

   Reassemble components

   Reconnect the electrical harness to the new sensor, reinstall any removed access covers or components, and reconnect the battery ground strap.

6. 6

   Prime and test the system

   Turn the key to the 'ON' position for at least 60 seconds to prime the system. Start the engine, run for a couple of minutes, and check for fuel leaks.

7. 7

   Clear fault codes

   Use a diagnostic tool or onboard display to clear stored codes and perform a functional check to ensure the code does not return.