Case IH F-5272-02 - ECU – Engine Control Unit (ECU) / Engine Control Module (ECM): ECU internal failure - Voltage ratio in ADC monitoring

This fault indicates that the Engine Control Unit (ECU) has detected an internal hardware or software failure. The Analog Digital Converter (ADC) inside the ECU is continuously monitored for plausibility using redundantly read input and test voltage inputs. When the voltage ratio check fails (e.g., the internal value exceeds the programmed threshold for 15 consecutive events), the ECU flags an internal fault.

• MAGNUM AFS Connect
• Case IH 240 Series Axial-Flow Combines
• Various Case IH tractors and equipment utilizing FPT (Fiat Powertrain Technologies) engines.

1. 1

   Check the battery voltage and ensure the battery is fully charged. Verify the voltage output from the alternator.

2. 2

   Inspect the wiring harness connections at the alternator and the ECU for proper seating, corrosion, or damage.

3. 3

   Check for multiple CAN bus fault codes. If present, test the entire CAN bus circuit (should be approximately 60 ohms between the CAN HI and CAN LO wires, or 108 - 132 ohms if checking specific terminating resistors).

4. 4

   Clear the error using a diagnostic tester to see if the fault is an active, hard fault or a temporary software anomaly.

1. 1

   Perform Electrical Diagnostics

   Complete the battery, alternator, and CAN bus checks listed above.

2. 2

   Clear and Retest

   Clear the fault code with an electronic service tool (EST) or diagnostic tester and cycle the machine's power.

3. 3

   Software/Dataset Calibration

   If the code returns, contact the dealer help desk to check if a software calibration or dataset update is available for the ECU.

4. 4

   Replace the ECU

   If the electrical supply is stable, the software is up to date, and the problem persists, the ECU has suffered a permanent internal failure. The ECU must be replaced and programmed to the machine.