Case IH 3179 (DTC 956B) - ECU – Engine Control Unit (ECU A-095): CAN communication failure between vehicle controller and ECU - BC2ECU2 message.

The Engine Control Unit (ECU) has lost Controller Area Network (CAN) communication with the main vehicle controller (Body Controller or VCM). When the BC2ECU2 message drops, the machine loses the vital data link between the engine and the rest of the vehicle's operational logic.

• MAXXUM T4E
• 240 Series Axial-Flow Combines (7240, 8240, 9240)
• Puma Series
• Magnum Series (MX210, MX230, MX255, MX285)
• A8000 Sugar Cane Harvester
• A8800 Sugar Cane Harvester
• A9900 Sugar Cane Harvester

1. 1

   Connect the Case IH Electronic Service Tool (EST) to see if the fault is currently active or intermittent.

2. 2

   Ensure no external power supply is improperly connected to the tractor, as voltage spikes can disrupt CAN communication.

3. 3

   Start the engine and run it at 2000 RPM. Check the battery voltage on the instrument cluster to rule out a faulty charging system or alternator causing voltage drops to the ECU.

4. 4

   Visually inspect the twisted-pair CAN wiring harness between the vehicle controller and ECU A-095. Flex the harnesses while the machine is on to check for intermittent breaks or shorts.

5. 5

   Check the ECU and Body Controller connectors for bent, pushed-back, or corroded pins.

1. 1

   Resolve voltage issues

   If the battery voltage test fails, repair the charging system (replace the alternator or batteries) before proceeding, as low voltage will cause CAN modules to drop offline.

2. 2

   Repair wiring

   If the harness flex test reveals a break, or if you find damaged pins at the ECU A-095 connector, repair the wiring harness. Ensure the CAN-High and CAN-Low twisted pair wires maintain their twist right up to the connector to prevent electromagnetic interference.

3. 3

   Software flash

   If the wiring and voltage are perfect, connect the EST and verify that the ECU A-095 has the correct, uncorrupted software. Reinstall/reflash the ECU software if necessary.

4. 4

   Replace the ECU

   If the internal resistor or the CAN transceiver has failed, and software reflashing does not clear the active code, the ECU A-095 must be replaced.