Case IH F-3511-12 - ECU – Engine Control Unit (ECU / ECM): ECU 5 volt sensor supply 3 out of range failure

The Engine Control Unit (ECU) has detected an abnormal voltage drop on its third 5-volt reference circuit. The fault triggers specifically when the ECU (module A-028) detects a voltage value lower than 189 mV for a period greater than 200 milliseconds on the associated sensor circuit.

• MAGNUM AFS Connect
• Austoft Sugarcane Harvesters A9900 series
• Austoft Sugarcane Harvesters A9000 series
• Austoft Sugarcane Harvesters A8800 series

1. 1

   Check if fault code 3112 (F-157-11) — 'Fuel gallery/rail pressure sensor voltage is above expected' — is also active. If it is, resolve that fault first.

2. 2

   Verify if the signal circuit of the fuel rail pressure sensor (designated as sensor B-FPT-09) has an open circuit condition.

3. 3

   Test the B-FPT-09 signal circuit for a short-to-ground condition, which is a primary cause of pulling the 5-volt supply out of range.

1. 1

   Inspect the Wiring Harness

   Visually inspect the wiring harness between the Engine ECU and the Fuel Rail Pressure Sensor (B-FPT-09). Look for chafed wires, melted insulation, or corroded pins at the connectors (specifically connector X-FPT_09 and ECU connector X-028C8).

2. 2

   Test the Circuit

   Using a multimeter, test the 5-volt supply wire for a short to ground. If a short is found, repair or replace the damaged section of the wiring harness.

3. 3

   Replace the Sensor

   If the wiring tests perfectly, the service manual indicates that the most likely cause is an internal failure of the Fuel Rail Pressure Sensor (B-FPT-09) pulling the voltage down. Replace the sensor.

4. 4

   ECU Software/Hardware Check

   If the wiring is intact and a new sensor does not resolve the issue, the failure could be an internal software or hardware fault within the ECU (A-028). The ECU may need to be reflashed by a dealer or replaced.