Case IH 520330-03 - BCM – BCM: CAN Bus B - short circuit to B+

Indicates a critical electrical fault where the CAN Bus B communication network has shorted to battery voltage (high source), which disrupts communication across the bus.

• MAGNUM AFS Connect
• Magnum 180, 200, 220, 240 AFS Connect
• Magnum 250, 280, 310, 340, 380 AFS Connect
• Magnum 400 AFS Connect

1. 1

   Stop the engine, remove the key, and ensure the working area is clear before disconnecting any electrical connections.

2. 2

   Inspect the electrical system and wiring harnesses associated with the BCM and CAN Bus B for loose connections, frayed insulation, or exposed wires.

3. 3

   Test the CAN Bus B lines (CAN_H and CAN_L) for a short to battery voltage (B+).

4. 4

   Disconnect modules on CAN Bus B one at a time to see if the short to B+ clears, which will isolate whether the short is in the main harness or a specific peripheral component.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the battery to prevent electrical arcing or further module damage.

2. 2

   Repair Wiring

   If the diagnostic checks revealed frayed insulation or a pinched wire shorting to a power source, repair or replace the damaged section of the wiring harness.

3. 3

   Replace Faulty Components

   If a specific module on CAN Bus B was found to be internally shorting the bus to B+, replace that component. If the BCM itself is internally shorted, it must be replaced.

4. 4

   Reassembly

   Reconnect all electrical connections. Close all access doors and reinstall all panels, guards, and shields that were removed during servicing.

5. 5

   Clear Codes

   Restore battery power, turn the key to the ON position, and use the diagnostic tool to clear the fault code and verify that CAN Bus B communication has been restored.