John Deere 94 – ECU (A00): Fuel Pressure Too Low

The Engine Control Unit (ECU) has detected that the fuel pressure is below the minimum threshold of 300 kPa (44 PSI). This signifies a restriction, leak, or component failure within the low-pressure side of the fuel delivery system, between the fuel tank and the high-pressure injection pump. This condition may negatively affect engine performance and could lead to operational issues such as a loss of power, engine derate, or failure to start.

• 9660 STS
• 9760 STS
• 9860 STS
• 9570 STS
• 9670 STS
• 9770 STS
• 9870 STS
• 9230
• 9330
• 9430
• 9530
• 9630
• 7R250
• 6420S
• 333D
• 329D
• 7250
• 7350
• 7450
• 7550
• 7750
• 7850

1. 1

   Check primary and secondary fuel filters for restrictions or clogs

2. 2

   Inspect the fuel system for air intrusion which can lead to a loss of prime

3. 3

   Check fuel lines for kinks or restrictions and clean the fuel suction screen in the tank

4. 4

   Monitor fuel pressure using the machine's service mode display if available

5. 5

   Inspect the fuel pressure sensor (a reading other than zero when disconnected indicates a faulty sensor)

6. 6

   Check the fuel check valve on the cylinder head for faults causing low pressure or long cranking times

1. 1

   Replace fuel filters

   Replace both the primary and secondary fuel filters to eliminate restrictions.

2. 2

   Drain water from fuel

   If the 'water in fuel' indicator is active, drain the water from the fuel filters and separator.

3. 3

   Inspect and clean fuel lines

   Blow out the fuel suction tube and ensure all fuel lines are clear of obstructions.

4. 4

   Test and replace lift pump

   Test the lift pump (transfer pump). If fuel pressure remains low after changing filters, replace the lift pump.

5. 5

   Inspect and replace fuel pressure sensor

   If diagnostic checks point to a faulty sensor (e.g., reading non-zero when disconnected), replace the fuel pressure sensor.

6. 6

   Check for air leaks

   Inspect seals, such as the one on the water sensor filter, for any potential air leaks into the system.

7. 7

   Contact dealer for advanced diagnostics

   If the problem persists after the above steps, contact a John Deere dealer to diagnose potential issues with the high-pressure pump or injector wiring.