Case IH 520598-04 - BCM – BCM: High power voltage supply c - out of range - low

The Body Control Module (BCM) is detecting that the voltage on its "High Power Supply C" circuit has dropped below the minimum acceptable operating threshold. This indicates a voltage drop, an open circuit, or a high-resistance connection on that specific power feed to the module.

• MAGNUM AFS Connect
• Magnum 180
• Magnum 200
• Magnum 220
• Magnum 240
• Magnum 250
• Magnum 280
• Magnum 310
• Magnum 340
• Magnum 380
• Steiger AFS Connect
• Optum AFS Connect

1. 1

   Verify that the tractor's batteries are fully charged and the alternator is outputting the correct voltage. Low system voltage can trigger this code.

2. 2

   Locate the cab/BCM fuse box. Check all fuses related to the Body Control Module, specifically looking for a blown fuse on the 'Supply C' circuit.

3. 3

   Inspect the main wiring harness connectors plugging into the BCM. Look for pushed-out pins, fretting, or green corrosion, which can cause high electrical resistance and a localized voltage drop.

4. 4

   Check the main cab and BCM ground straps to ensure they are tight and free of rust/paint.

1. 1

   Power Down

   Turn off the tractor, remove the key, and disconnect the negative battery cable to prevent electrical shorts during testing.

2. 2

   Locate the BCM

   Access the Body Control Module (typically located inside the cab console or behind the trim panels, depending on the exact Magnum cab configuration).

3. 3

   Test the Circuit

   Reconnect the battery. Using a digital multimeter, probe the "High Power Supply C" pin at the BCM connector (refer to the specific tractor's wiring schematic for the exact pinout).

4. 4

   Trace the Voltage Drop

   If the voltage at the BCM pin is significantly lower than battery voltage (or 0V), trace the wire back to the fuse panel. Repair any chafed wires, broken splices, or corroded connectors in the harness. If the fuse is blown, check the circuit for a short to ground before replacing the fuse.

5. 5

   Clean Connections

   If the voltage is correct but the connector was loose or dirty, clean the pins with electrical contact cleaner, apply dielectric grease, and securely seat the connector.

6. 6

   Module Replacement

   If the wiring, fuses, and inputs are all verified to be supplying full battery voltage under load, but the BCM continues to log the 520598-04 code, the BCM has an internal hardware failure and must be replaced and reprogrammed by a dealer.