Case IH 3112 (DTC 1425) - ECU – Engine Control Unit (ECU): Fuel rail pressure sensor voltage is higher than expected.

The control module is receiving a voltage signal from the fuel rail pressure sensor that exceeds the normal operating parameters, which can be caused by an electrical fault (like a short to power), a faulty sensor, or an actual mechanical over-pressurization of the fuel rail.

• MAXXUM T4E
• 240 Series Axial-Flow Combines (7230, 8230, 9230)
• MX Series
• TG Series
• Magnum
• Steiger
• Puma
• Maxxum
• Farmall models
• A8810 Sugar Cane Harvesters

1. 1

   Check if the tractor battery has been connected to an external power supply (jump starter or charger) which can cause voltage spikes

2. 2

   Perform a Key-On, Engine-Off (KOEO) test to check if the signal wire outputs approximately 0.5 volts

3. 3

   Verify the 5-volt reference is present between the connector's Fuel Pressure Sensor pin 3 (power) and pin 1 (ground)

4. 4

   Check the ground circuit by back-probing the connector (should be less than 50 mV on the sensor ground)

5. 5

   Inspect the fuel pressure regulator on the high-pressure pump and check fuel return lines for mechanical restrictions

1. 1

   Clear External Interference

   Disconnect any external battery chargers or power supplies. Clear the fault code and cycle the key to see if the code returns.

2. 2

   Inspect Wiring

   Visually inspect the wiring harness leading to the fuel rail pressure sensor for chafing, bare wires, or a short to power. Repair any damaged CAN bus or sensor wiring connectors.

3. 3

   Test and Replace Sensor

   If the 5V reference and ground circuits test perfectly, but the sensor output voltage is still out of range (higher than expected) during the KOEO test, the sensor has failed internally. Replace the fuel rail pressure sensor.

4. 4

   Address Mechanical Over-pressure

   If the sensor tests fine but the code persists while the engine is running, clear any blockages in the fuel return lines. If the return lines are clear, the fuel quantity valve (M-Prop/fuel control actuator) on the high-pressure pump or the pressure relief valve may be stuck, requiring replacement of the actuator or pump.