ECU 521214.09 – Incorrect CAN Bus Message, Information from EIC Control Software. John Deere System Advisory.

ECU 521214.09 (ECU )

Code: 521214.09



This diagnostic trouble code is generated if a data transfer problem occurs between the Engine Interface Controller (EIC) control software and the ECU control software. The CAN Bus message (enable signal from immobilizer) sent by the EIC control software cannot be received by the ECU.


The vehicle may have limited or no function due to the inability of the ECU to receive the necessary enable signal from the immobilizer via the CAN Bus.


  • Inspect CAN Bus Wiring and Connections: Check for damaged, frayed, or loose wiring and connectors associated with the CAN Bus between the EIC and the ECU. Repair or replace as necessary.
  • Test CAN Bus Communication: Use diagnostic tools to test the CAN Bus communication between the EIC and the ECU. Ensure that there are no interruptions or data transfer issues.
  • Check EIC and Immobilizer: Verify that the EIC and immobilizer are functioning correctly and sending the enable signal properly.
  • Verify ECU Reception: Ensure that the ECU is capable of receiving CAN Bus messages and is functioning correctly.
  • Reset ECU and Monitor System: After resolving the issue, reset the ECU to clear the fault code and monitor the system to ensure normal operation.


Maintaining proper communication between the EIC and the ECU via the CAN Bus is essential for vehicle operation. Regular inspections and timely maintenance can help prevent communication-related issues.

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