Case IH 3680 (F-3607-14) – Engine Control Module (ECM): ECM internal failure - Engine speed limitation via fuel injection cut off is active

The engine control system has detected an internal fault or an unsafe operating condition (such as an overspeed event or torque mismatch) and has actively intervened to limit the engine speed by cutting off the fuel injection.

• VESTRUM CVX
• 240 Series Axial-Flow Combines
• Magnum AFS Connect series
• Case N-Series Tier 4 Final machines

1. 1

   Check for associated fault codes that might force the ECU into a protective fuel-cut state (e.g., engine overspeed F-190-00, fuel pressure plausibility errors, or temperature sensor drift codes 3686 or 3687)

2. 2

   Verify battery voltage and check the wiring harness and fuses supplying power to the ECM to rule out voltage spikes or drops

3. 3

   Check for corrupted dataset calibration in the ECU software

1. 1

   Connect diagnostic tool

   Connect the Case IH diagnostic tool (EASy tool / Electronic Service Tool) to the machine's diagnostic port.

2. 2

   Re-flash ECM

   Attempt to re-flash the Engine Control Module with the latest software calibration dataset.

3. 3

   Clear codes and test

   Clear the fault codes and cycle the key to see if code 3680 returns.

4. 4

   Evaluate ECM

   If the internal failure persists after a successful re-flash and wiring verification, the ECM is permanently defective and must be replaced.

5. 5

   Disconnect batteries

   Disconnect the batteries before removing the ECM.

6. 6

   Remove ECM

   Unplug the engine wiring harnesses from the ECM and unbolt the module from its mounting bracket.

7. 7

   Install replacement ECM

   Install the replacement ECM and reconnect the harnesses.

8. 8

   Program new ECM

   Important: A newly installed ECM will be blank or locked. It must be programmed/flashed by an authorized Case IH dealer with the correct software for your specific machine's PIN/serial number before the engine will start.