Case IH 3657 – Engine Control Unit (ECU): CAN Bus Received frames: Timeout Error of CAN-Receive-Frame CM1BC

This code indicates a communication failure on the machine's Controller Area Network (CAN) bus. Specifically, the Engine Control Unit (ECU) has timed out while waiting to receive the 'CM1BC' message frame from the Body Computer or Vehicle Control Module (VCM).

• Farmall
• skid steer
• tractors
• skid steers
• compact track loaders
• wheel loaders
• Magnum
• Steiger
• MXU

1. 1

   Inspect the vehicle wiring harness for disconnected, broken, or short-circuited CAN cables between the Engine Control Unit and the Body Computer/Instrument Cluster.

2. 2

   Check the installation and proper connection of the Engine Control Unit and the Body Computer to the CAN vehicle network, looking for pushed, bent, or corroded pins in the connectors.

3. 3

   Verify the correct operating conditions of the CAN controller.

4. 4

   Use the Case IH Electronic Service Tool (EST) to check the CAN configuration in the Body Computer to ensure it is properly programmed to broadcast the CM1BC message.

1. 1

   Verify fault code

   Connect the Case IH Electronic Service Tool (EST) to the machine's diagnostic port to verify the active 3657 fault code and check for any other related CAN bus off/timeout codes.

2. 2

   Inspect wiring harness

   Perform a visual and multimeter inspection of the CAN bus wiring harness between the EDC and the Body Computer. Test for continuity and ensure there are no shorts to ground or power.

3. 3

   Test terminating resistors

   Test the CAN bus terminating resistors. The CAN network requires 120-ohm terminating resistors at each end of the bus to prevent signal reflection.

4. 4

   Repair or replace wiring

   If a wiring break or short is found, repair the harness using an OEM wiring repair kit or replace the affected harness section.

5. 5

   Diagnose CAN controller

   If the wiring and terminating resistors test good, but the CM1BC message is still not being transmitted, the fault likely lies within a defective CAN controller inside either the Body Computer (VCM) or the Engine Control Unit (EDC).

6. 6

   Update or replace Body Computer

   Flash/update the Body Computer with the latest dataset/configuration using the EST. If the module will not communicate or broadcast the frame, replace the Body Computer/VCM.

7. 7

   Clear codes and test

   Clear the fault codes using the EST and test-run the machine to verify the repair.