Case IH 3510-04 - DEC – Engine Control Unit (ECU): 5 volt sensor supply instance 2 electrical circuit fault voltage below normal

The Engine Control Unit (ECU) has detected the voltage on the 5-volt DC sensor power supply circuit #2 has dropped below its normal operating range (typically below 4.44 volts). This usually means there is a short to ground in the wiring harness, a failed (internally shorted) sensor pulling the circuit voltage down, or an internal failure within the ECU.

• MAGNUM AFS Connect
• Axial-Flow Combines (7230, 8230, 9230)
• Tractors (Puma 230, CVX 140/150/160/175/195, Farmall 120A)
• Equipment utilizing 6.8L and 9.0L engines

1. 1

   Consult the specific machine's wiring schematic to identify exactly which sensors are powered by the 5 Volt Supply #2 circuit (commonly Engine Oil Pressure, Intake Manifold Pressure, Fuel Pressure, Barometric Pressure, and Crankcase Pressure sensors)

2. 2

   Perform a sensor isolation test by disconnecting the sensors on this 5V circuit one at a time to see if the 5V reference voltage returns to normal or if the code changes to an open circuit code

3. 3

   Use a multimeter to check the wiring harness for continuity and shorts to ground between the ECU pins and the sensor connectors, looking for chafed, melted, or pinched wires

4. 4

   Test the battery supply to the ECU to ensure it is not unusually low, and verify if the ECU pin outputs 5V when the harness is completely isolated

1. 1

   Power Down

   Turn off the machine and turn the battery disconnect switch to the OFF position.

2. 2

   Inspect Wiring

   Visually inspect the engine wiring harness routing, paying close attention to areas where the harness rubs against the engine block, brackets, or is exposed to high heat.

3. 3

   Test and Isolate

   Turn the key ON (engine OFF). Perform the sensor isolation test described in the diagnostic checks.

4. 4

   Replace the Faulty Component

   If a sensor is shorted: Replace the specific sensor that pulled the voltage down and clean the connector with electrical contact cleaner. If the harness is shorted: Repair the damaged section of the wire using OEM-approved splicing methods or replace the affected engine harness section. If the ECU is faulty: Replace or reprogram the Engine Control Unit.

5. 5

   Verify Repair

   Reconnect all components, turn the key ON, and clear the inactive fault codes using a diagnostic tool. Start the engine and verify that the 3510-04 code does not return and that engine derate is lifted.