Case IH 3309 (DTC 1865) - ECU – Engine Control Unit (ECU): Fuel rail pressure has exceeded maximum limit.

The engine's control system has detected that the fuel pressure within the high-pressure common rail has spiked beyond safe operating parameters (greater than 2,000 bar / 29,000 psi).

• MAXXUM T4E
• 240 Series Axial-Flow (7240, 8240, 9240)
• 7230
• 8230
• 9230
• Puma series
• Magnum series (245, 275, 305, 335)
• Steiger series (280, 330, 335)
• Maxxum series
• Farmall series (90C through 120U)

1. 1

   Check for other active fuel system faults (3137, 3910, 3293, or 3301) which must be diagnosed first

2. 2

   Inspect wiring harness and connectors to the Fuel Rail Pressure Sensor (B-015) and Fuel Metering Unit for chafed wires, corrosion, or loose pins

3. 3

   Test the Fuel Rail Pressure Sensor output voltage to ensure it is not internally shorted or reading out of calibration

4. 4

   Inspect the mechanical fuel metering unit on the high-pressure injection pump to see if it is stuck open or failing to regulate flow

1. 1

   Read All Codes

   Connect your diagnostic scan tool and pull all active and stored DTCs from the Engine ECU.

2. 2

   Address Metering/Deviation Faults

   If codes 3137, 3910, 3293, or 3301 are present, troubleshoot the fuel metering unit (also known as the fuel pressure control actuator/valve) and its wiring harness first. A failing metering unit will often cause the pressure to spike, triggering code 3309 as a secondary symptom.

3. 3

   Inspect Wiring and Connectors

   Inspect the wiring harness leading to the Fuel Rail Pressure Sensor (B-015) and the Fuel Metering Unit. Look for chafed wires, corrosion, or loose pins that could cause erratic voltage readings to the ECU.

4. 4

   Test the Fuel Rail Pressure Sensor

   Verify the sensor's output voltage. If the sensor is internally shorted or reading out of calibration, it will falsely report a maximum pressure condition to the ECU. If the wiring is good but the sensor reading is erratic or pegged at maximum, replace the sensor.

5. 5

   Inspect/Replace the Fuel Metering Unit

   If the sensor is functioning correctly and accurately reporting a massive over-pressure event, the mechanical fuel metering unit on the high-pressure injection pump is likely stuck open or failing to regulate flow. Replace the fuel metering unit/actuator.