John Deere 157.04 – ECU: Fuel Rail Pressure Sensor Signal Voltage Is Too Low (ECU) / Fuel Rail Pressure Signal Out Of Low Range

The Engine Control Unit (ECU) detects that the input voltage from the Fuel Rail Pressure Sensor has dropped below the sensor's minimum low-voltage specification. This indicates an electrical fault (such as a short to ground or an open circuit) rather than an actual mechanical fuel pressure drop.

• 5085E
• 5090E
• 5090EL
• 5100E
• 5065M
• 5075M
• 5085M
• 5100M
• 5100MH
• 5100ML
• 5115ML
• 5095M
• 5095MH
• 5105M
• 5015ML
• 5090M
• 5115M
• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 7230
• 8330
• 9230
• 9330
• 9430
• 9530
• 9630
• S650
• S660
• S670
• S760
• S770
• S780
• S790
• 130G
• 135D
• 290GLC
• 204L
• 304L
• 344K
• 444K
• 524K
• 624K
• 310J
• 310K
• 410K
• 640L
• 648L
• 748H

1. 1

   Visual Inspection: Check the wiring harness leading to the high-pressure fuel rail sensor and the suction control valve. Look for chafed wires, melted insulation, or loose connections.

2. 2

   Connector Pin Test: Disconnect the sensor and inspect the terminals for corrosion, pushed-back pins, or moisture.

3. 3

   Supply Voltage Test: Using a multimeter, verify that the sensor is receiving the correct reference voltage (typically 5V) from the ECU.

4. 4

   Resistance/Continuity Test: Test the signal wire and ground wire for continuity back to the ECU. Check for a short to ground on the signal wire, which is the most common cause of a Voltage Too Low code.

1. 1

   Safety First

   Turn off the ignition. Crucial: High-pressure fuel systems can cause severe injury. Allow the engine to cool and relieve the fuel system pressure before loosening any fittings or sensors.

2. 2

   Repair Wiring

   If the diagnostic tests revealed a short to ground or an open wire in the OEM harness, splice and repair the affected wire using John Deere approved heat-shrink connectors.

3. 3

   Replace the Sensor

   If wiring is good, disconnect the electrical connector from the Fuel Rail Pressure Sensor. Clean the area around the sensor to prevent debris from entering the fuel rail. Unthread the faulty sensor from the fuel rail. Install the new sensor and torque it to the specifications listed in your specific engine's OEM service manual.

4. 4

   Reassembly and Testing

   Reconnect the electrical harness. Prime the fuel system if necessary. Start the engine, let it warm up, and check for fuel leaks around the sensor threads.

5. 5

   Clear Codes

   Use a diagnostic tool to clear the 000157.04 code from the ECU and verify it does not return during operation.