Case IH 3271 – Engine ECU: Fuel Low Pressure Sensor -(via CAN) No Signal

This code indicates a communication or electrical failure where the engine control module is no longer receiving a valid signal from the fuel low-pressure sensor over the CAN (Controller Area Network) bus. This sensor monitors the supply pressure of the fuel before it reaches the high-pressure injection pump.

• Magnum 235 - 340 (Series 4)
• Steiger series
• Puma series (165, 180, 195, 210, 225 CVX)
• Axial-Flow series (5130, 6130, 7230, 8230, 9230)

1. 1

   Visually inspect the fuel low-pressure sensor (typically located on or near the fuel filter housing or low-pressure supply line) for physical damage or fuel leaks.

2. 2

   Disconnect the sensor and inspect the wiring harness connector for corrosion, pushed-back pins, or moisture/debris.

3. 3

   Verify that the sensor is receiving its 5V reference supply voltage and has a solid ground. Check the signal wire for continuity back to the Engine ECU and test for a cable break or short circuit to ground/power.

4. 4

   Verify the integrity of the CAN bus lines connecting the sensor node to the Engine ECU.

1. 1

   Power Down

   Turn off the machine and disconnect the negative battery terminal to prevent electrical spikes.

2. 2

   Access the Sensor

   Relieve any residual low-pressure fuel system pressure if required by the service manual.

3. 3

   Remove the Sensor

   Unplug the electrical connector from the fuel low-pressure sensor. Use the appropriate wrench to unthread the sensor from the fuel housing.

4. 4

   Install the New Sensor

   Thread the new sensor into the housing. Torque to the manufacturer's specification (do not over-tighten, as this can damage the sensor diaphragm).

5. 5

   Reconnect

   Plug the electrical connector back in, ensuring it clicks and locks securely.

6. 6

   Prime the System

   Reconnect the battery. Turn the key to the ON position to allow the electric lift pump to prime the fuel system and bleed out any air.

7. 7

   Clear Codes and Test

   Connect a diagnostic tool (such as the Case IH EST) to clear the 3271 fault code. Start the engine, check for fuel leaks around the new sensor, and verify that the code does not return.