Case IH 5657-09 - VCM – VCM: Engine anti-tamper checksum not sent by engine controller

The VCM continuously monitors the Engine ECU over the CAN bus for a specific security checksum to verify that the engine software is authentic and unaltered. If the VCM does not receive this checksum, it triggers code 5657-09.

• MAGNUM AFS Connect
• Steiger AFS Connect
• Optum AFS Connect

1. 1

   Verify ECU Tuning/Modifications: Check if the tractor has recently been 'unlocked,' tuned, or 'deleted' by a third party. Aftermarket tuning often bypasses or removes the anti-tamper checksum.

2. 2

   Check CAN Bus Communication: Verify the integrity of the CAN bus communication lines between the Engine ECU and the VCM.

3. 3

   Check for Software Mismatches: Verify if either the VCM or the Engine ECU was recently replaced or updated independently, causing a software mismatch.

1. 1

   Restore OEM Software

   If the tractor's Engine ECU has been modified with an aftermarket tune, connect the CNH Electronic Service Tool (EST) and reflash the Engine ECU back to the factory OEM software to restore the anti-tamper checksum.

2. 2

   Update Modules

   If the tractor is completely stock, use the CNH EST to check for available software updates for both the VCM and the Engine ECU. Flash both modules to the latest software versions to ensure they are communicating with the same security protocols.

3. 3

   Repair Wiring

   If the software is correct but the modules cannot communicate, trace the CAN bus wiring harness between the Engine ECU and the VCM. Repair any broken wires, corroded pins, or loose connectors.

4. 4

   Replace Bricked Modules

   If the Engine ECU was permanently damaged or 'bricked' by an improper third-party unlock attempt, the ECU must be physically replaced and programmed by a dealer.