Case IH F-1043-15 - ECU – Engine Control Module (ECM): Monitoring of internal 12V supply SRC_HIGH Error

The Engine Control Module (ECM) monitors its internal 12-volt supply voltage. If the controller determines that this voltage value is higher than the expected threshold, it logs this fault. This is typically caused by a defect in the wiring harness (short to a high voltage source), an electrical failure in one of the connected sensors, or an internal failure within the ECM itself.

• MAGNUM AFS Connect
• Case IH 240 Series Combines
• Case IH Magnum Tractors (e.g., MX210, MX230, MX255, MX285)
• Case IH Puma and Maxxum series tractors

1. 1

   Verify that the tractor's battery power supply has not been connected to an external power supply (such as a high-voltage jump starter or incorrect battery charger). If an external supply is connected, disconnect it and test the system for normal operation.

2. 2

   Check the wiring for the correct voltage supply to all connected sensors

3. 3

   Visually inspect the wiring harnesses and connectors for damaged, bent, or pushed-out pins, corroded terminals, or broken wires that could be causing a short circuit to a high voltage source

4. 4

   Check the electrical integrity of the connected sensors to ensure one of them is not shorting the 12V reference circuit

1. 1

   Disconnect External Power

   If a jump box or external charger is attached, remove it, cycle the key, and see if the code clears.

2. 2

   Inspect and Repair Wiring

   If the code remains, trace the engine wiring harness. Repair any shorts to battery voltage or damaged wires found in the 12V sensor supply circuits.

3. 3

   Test Sensors

   Unplug sensors on the 12V circuit one by one to see if the voltage returns to normal and the code goes inactive. Replace any internally shorted sensors.

4. 4

   Software Flash

   Check the ECU for the appropriate software version and re-flash if necessary to rule out a software glitch.

5. 5

   Replace the ECM

   If the wiring harness is completely intact, the sensors are functioning correctly, and the fault remains active, the ECM has suffered an internal failure and must be replaced.