Case IH F-641-31 - ECU – ECU: CAN communication error between the ECU and the eVGT actuator

The eVGT (Electronic Variable Geometry Turbocharger) utilizes a "smart actuator" that contains its own built-in analog-to-digital converter and CAN bus interface. This code triggers when the engine computer loses network communication with this actuator, meaning it can no longer command the turbocharger's vane positions to control exhaust backpressure and boost.

• MAGNUM AFS Connect
• Case IH Magnum AFS Connect tractors
• Case IH Steiger & Quadtrac tractors
• Case IH 240 Series Axial-Flow Combines

1. 1

   Check the dedicated eVGT power supply fuse (often F-203, 20A Mini Yellow) to ensure it is not blown.

2. 2

   Inspect the EVGT actuator relay for proper operation, checking for continuity and ensuring there is no short to voltage in the harness.

3. 3

   Visually inspect the wiring harness between the ECU and the eVGT actuator for chafing, melting, or corrosion at the connectors.

4. 4

   Test the CAN High and CAN Low communication lines at the actuator connector for proper voltage and network resistance (typically ~60 ohms across the CAN network with the battery disconnected).

1. 1

   Disconnect Power

   Always disconnect the machine's battery before servicing ECU wiring or smart actuators.

2. 2

   Resolve Power/Ground Issues

   If the 20A fuse is blown or the relay fails the continuity test, replace them.

3. 3

   Repair Wiring

   If a short or open circuit is found in the harness between the ECU and the actuator, repair the damaged section of the wiring or replace the harness.

4. 4

   Replace the Actuator

   If the wiring, fuses, and relays all test good, the CAN module inside the eVGT smart actuator has likely failed internally. Remove the mounting hardware and linkage connecting the actuator to the turbocharger and install a new eVGT actuator.

5. 5

   Clear Codes and Calibrate

   Reconnect the battery. Use the Case IH Electronic Service Tool (EST) to clear the fault codes. The new actuator may require an initialization/learn procedure via the EST so the ECU can learn its end-stops.

6. 6

   Test Run

   Bring the engine up to operating temperature and run it under load to verify the code does not return and boost pressures are normal.