Case IH 520596-04 - BCM – BCM: High power voltage supply a - out of range - low

This code indicates that the voltage being supplied to the high-power input circuit "A" of the Body Control Module (BCM) has dropped below the acceptable normal operating range.

• MAGNUM AFS Connect
• Case IH Magnum AFS Connect (Models 180, 200, 220, 240, 250, 280, 310, 340, 380, and 400)
• Case IH Steiger AFS Connect

1. 1

   Check the battery isolator terminals (CLOSED terminal X-147 pin 2 and OPEN terminal X-147 pin 1) to ensure power is properly passing to the battery fuse module.

2. 2

   Inspect the battery fuse module for blown fuses or loose connections that supply unswitched power to the BCM.

3. 3

   Inspect the wiring harness supplying power to the BCM high-power A circuit for corrosion, chafing, or loose pins at the BCM connectors.

4. 4

   Verify if the BCM is stuck in snooze mode due to a lack of wake-up inputs or communication traffic, which can affect power distribution.

1. 1

   Disconnect Power

   Turn off the key and open the manual battery disconnect switch to safely isolate the electrical system.

2. 2

   Inspect Cables

   Trace the main power cables from the battery isolator and battery fuse module to the BCM. Clean any corroded grounds or power terminals.

3. 3

   Test Voltage

   Using a multimeter, test the voltage directly at the BCM high-power input pins. If the voltage is low at the connector, the issue is in the wiring harness or a relay/fuse upstream. If the voltage is normal at the connector but the code persists, the fault is internal to the BCM.

4. 4

   Repair Wiring/Fuses

   Replace any blown fuses in the battery fuse module and repair any damaged wiring in the high-power supply circuit.

5. 5

   Software Update / Module Replacement

   If the physical circuits are intact, check if the BCM requires a software update. Case IH has issued Product Improvement Programs (PMPs) for BCM software on AFS Connect models. If an update does not resolve the internal voltage drop, the BCM must be replaced.

6. 6

   Clear Codes

   Reconnect the battery, turn the key on, and use the Case IH diagnostic tool to clear the fault code and verify the repair.