John Deere ECU000157.17 – ECU: Fuel Rail Pressure Low During Starting

The Engine Control Unit (ECU) has failed to detect sufficient fuel pressure in the common rail system during the engine cranking process. Specifically, the fuel rail pressure has not reached the minimum required threshold of 10 MPa (1450 psi) within approximately five seconds of cranking. This lack of pressure prevents the fuel injectors from operating correctly, leading to a no-start or hard-starting condition. This is typically caused by insufficient fuel supply, fuel filtration issues, or a malfunction in the high-pressure fuel delivery components.

• 850J
• 850JR
• 3039R
• 4044R
• 2025r
• 8R Series
• 9R Series
• 648H

1. 1

   Check fuel level and quality by draining a sample from the fuel filter into a clear container to inspect for water, debris, or rust

2. 2

   Inspect primary and secondary fuel filters for clogs or contamination

3. 3

   Check for air in the fuel system by inspecting all fuel lines and connections between the tank, lift pump, and high-pressure pump for cracks or loose fittings (installing a clear hose on the supply line can help visualize air bubbles)

4. 4

   Verify low-pressure fuel pump (lift pump) operation by listening for it to run with the key in the 'ON' position, and perform a flow test (target flow is approximately 32 oz/one quart per minute)

5. 5

   Inspect electrical wiring harnesses and connectors for the fuel rail pressure sensor and the suction control valve (SCV) for damage, corrosion, or loose connections

1. 1

   Bleed the fuel system

   Turn the key to the 'ON' position for at least 60 seconds to allow the electric lift pump to prime the system. For systems with a manual primer, operate the primer until a steady, bubble-free flow of fuel is observed at the filter head and high-pressure pump inlet.

2. 2

   Test fuel pressure relief valve

   Remove the return line from the relief valve on the common rail. Crank the engine; if a significant amount of fuel flows out of the valve during cranking, the valve is sticking open and must be replaced.

3. 3

   Diagnose Suction Control Valve (SCV)

   Unplug the SCV and attempt to start the engine. If the engine starts (even if it runs rough), the SCV is likely faulty and should be replaced. Note: This is an unrecommended field test as it forces the system to full pressure, potentially damaging the pressure relief valve.

4. 4

   Test and replace fuel rail pressure sensor

   Check the sensor for a 5V reference signal, a good ground, and monitor the signal wire's output during cranking with a multimeter or oscilloscope. Replace the sensor if readings are incorrect.