Case IH 3285 (DTC E42D) - ECU – Engine Control Unit (ECU): ECU internal failure - Sensor 5 volt supply 3

The Engine Control Unit (ECU) provides three independent 5.0V reference voltage supplies to various engine and machine sensors. These voltages are continuously monitored by internal hardware within the ECU to ensure they remain within a specific operating range. This fault is triggered when the reference voltage for "Sensor Supply 3" falls out of the acceptable range, indicating a short, an overload, or an internal module failure.

• MAXXUM T4E
• Puma Series (140, 155, 160, 165, 180, 195, 200, 210)
• Magnum Series
• Steiger Series
• 240 Series Flagship Axial-Flow Combines (7240, 8240, 9240)
• A8000 / A8800 Series Sugar Cane Harvesters

1. 1

   Check for active faults, specifically fault 3112 (DTC 1425) - 'Fuel rail pressure sensor voltage is higher than expected'. Resolving the 5V supply issue will often clear this.

2. 2

   Verify that no external power supply (like a booster or unapproved aftermarket accessory) is improperly connected to the tractor.

3. 3

   Start the engine and run it at 2000 RPM. Check the battery voltage on the instrument cluster to ensure the alternator/charging system is not overcharging or failing.

4. 4

   Inspect the signal circuit for the B-015 Common Rail Pressure Sensor for rubbed-through wires or shorts to ground.

5. 5

   Check related solenoids on the circuit (such as the high range clutch solenoid) for resistance. Resistance should typically measure between 8 - 11 Ohms.

1. 1

   Disconnect external devices

   Remove any external power supplies or aftermarket monitors tied into the engine harness.

2. 2

   Inspect and repair wiring

   Trace the wiring harness for the Sensor 3 supply circuit (specifically checking the B-015 Fuel Rail Pressure Sensor pigtail). Repair any damaged, melted, or shorted wires.

3. 3

   Test and replace shorted sensors

   Unplug sensors on the 5V Supply 3 circuit one by one. If the 5V reference returns to normal upon unplugging a specific sensor (like the rail pressure sensor), replace that sensor.

4. 4

   Software reset or reflash

   If the wiring and sensors are intact, the ECU A-095 may have experienced a software logic error. Have a certified Case IH technician use the Electronic Service Tool (EST) to attempt a software reset or reflash.

5. 5

   Replace the ECU

   If the ECU A-095 cannot be reflashed, or if the internal hardware regulating the 5V supply is permanently burned out, remove and replace the Engine Control Unit.