Case IH 3455 – Engine Control Unit (ECU): Fuel pre-filter clog or circuit failure

The Engine Control Unit senses that the fuel pressure in the gear pump/feed line is very low (less than 0.60 bar / 8.70 psi) coming from the fuel pre-filter clogging pressure sensor (B-9006), indicating a clogged pre-fuel filter and danger of fuel starvation.

• Steiger T4B
• 240 Series Axial-Flow Combines
• Boomer compact tractors (33/37)
• Farmall series (35A/35C/40C/50C)
• Steiger
• Magnum tractors

1. 1

   Verify that there is adequate fuel in the tank and check for heavy water contamination or gelling.

2. 2

   Check the condition of the fuel pre-filter and verify the date/hours of the last maintenance service to see if the filter is past its service life.

3. 3

   Inspect the fuel feed lines from the tank to the pre-filter and from the pre-filter to the pump for kinks, damage, or physical restrictions.

4. 4

   Inspect the wiring harness leading to the B-9006 pressure sensor for chafed wires, disconnected plugs, or corrosion at the sensor connector.

1. 1

   Relieve pressure and drain

   Shut down the engine. Locate the fuel pre-filter/water separator assembly. Drain the fuel/water separator bowl to check for excessive water or debris.

2. 2

   Replace the pre-filter

   Remove the old fuel pre-filter element. Clean the housing and install a new OEM pre-filter element. Lubricate the new filter gasket with clean diesel fuel before tightening.

3. 3

   Prime the fuel system

   Use the manual or electric primer pump to bleed air from the fuel system until the filter housing is full and pressure is restored.

4. 4

   Test the sensor circuit

   If replacing the filter does not resolve the code, use a multimeter to verify continuity and check for proper reference voltage at the B-9006 sensor harness.

5. 5

   Replace the sensor

   If the wiring is intact, the filter is new, and the code persists, the B-9006 pressure sensor has likely failed internally and must be replaced.

6. 6

   Clear codes and verify

   Clear the DTC 31E5 / 3455 from the Engine ECU using a diagnostic tool. Run the engine and verify that the fuel pressure reading at the pre-filter now exceeds the 0.60 bar (8.70 psi) minimum threshold.