Case IH F-168-01 - ECU – Engine Control Unit (ECU): Electrical System Voltage : Low

The electrical power supply connections are providing a voltage that is lower than expected (below 10.2V for a 12V system or below 16 VDC for a 24V system).

• MAGNUM AFS Connect
• Magnum series tractors (MX210, MX230, MX255, MX285)
• Puma series tractors
• Farmall series tractors
• Axial-Flow Combines (240 series, 7230, 8230, 9230)

1. 1

   Verify the diagnostic code is currently ACTIVE with the engine running and ensure no external battery charger is connected.

2. 2

   Measure the voltage directly at the battery posts using a multimeter.

3. 3

   Inspect the battery wires from the ECM back to the battery compartment for failed wiring in the machine harness.

4. 4

   Inspect the power relay and check for a poor connection in the ground circuit, as well as power and ground connections directly at the ECM.

5. 5

   Verify the alternator output to ensure it is actively charging the system while the engine is running.

1. 1

   Address the Battery

   If the battery voltage measured at the posts is below specification, charge the battery fully and load-test it. Replace the battery if it fails the load test.

2. 2

   Repair Wiring/Connections

   Clean and tighten all battery cable connections and ground straps. Repair or replace any corroded, chafed, or broken wires in the machine harness between the battery, alternator, and ECU.

3. 3

   Replace the Alternator

   If the engine is running but the alternator is not producing sufficient charging voltage, replace the alternator.

4. 4

   ECU Replacement

   If the battery, alternator, and all wiring/grounds test perfectly, replace the ECU as a last resort.