Case IH F-95-15 - ECU – Engine Control Unit (ECU): Fuel filter clog or circuit failure

The engine management system has detected a restriction in the fuel delivery system (a clogged fuel filter) OR there is an electrical fault (such as an open circuit, short to ground, or short to power) in the fuel filter restriction switch/sensor circuit. When this code is active, the machine may experience a full power loss or be automatically reduced to low idle speed to protect the engine.

• MAGNUM AFS Connect
• 240 Series Axial-Flow Combines (Models 5140, 6140, 7140, 7240, 8240, 9240)
• Magnum
• Steiger
• Maxxum
• Farmall

1. 1

   Visually inspect the primary and secondary fuel filters for obvious signs of heavy contamination, gelling (in cold weather), or water in the separator (diagnoses clogged filter cause).

2. 2

   Inspect the wiring harness leading to the fuel filter restriction switch/sensor for chafed wires, broken connections, or melted insulation (diagnoses circuit failure cause).

3. 3

   Disconnect the sensor plug and check for corrosion, moisture, or pushed-back pins (diagnoses circuit failure cause).

4. 4

   Use a multimeter to test the fuel filter switch for continuity. If the filter is known to be clean but the switch reads as restricted, open, or shorted, the sensor itself has failed (diagnoses sensor failure cause).

1. 1

   Shut down the engine and disconnect the battery.

   Shut down the engine, remove the key, and allow the engine to cool. Disconnect the battery if you will be repairing wiring.

2. 2

   Drain the housing.

   Place a catch pan under the fuel filter assembly. Open the drain valve at the bottom of the fuel/water separator to drain the housing.

3. 3

   Remove the filter.

   Using a filter wrench, unscrew the spin-on fuel filter or open the cartridge housing to remove the element.

4. 4

   Clean and inspect the housing and sensor.

   Wipe the filter housing base clean. Inspect the restriction sensor mounted on the housing. If the diagnostic checks revealed a faulty sensor or damaged wiring, replace the sensor or splice in a new pigtail connector now.

5. 5

   Install the new filter.

   Lubricate the sealing O-ring of the new fuel filter with clean diesel fuel. Thread the filter on by hand until the gasket makes contact, then tighten according to the manufacturer's specifications (usually 3/4 to 1 full turn).

6. 6

   Prime the fuel system.

   Turn the ignition key to the ON position (without starting the engine) to allow the electric lift pump to prime the system, or use the manual primer plunger on the filter housing until resistance is felt.

7. 7

   Clear codes and test.

   Start the engine. If the machine was in an emergency shut-off or low-idle state, verify that full power is restored. Use a diagnostic tool to clear the stored DTC 4BB5 code. Check for leaks around the new filter.