Case IH 520597-03 - BCM – BCM: High power voltage supply b - out of range - high

Voltage being supplied to the "B" high-power circuit of the control module is exceeding the maximum allowable threshold. This is typically caused by an overcharging alternator, a wiring harness shorted to a higher voltage source (B+), or an internal failure within the module's voltage monitoring circuit.

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

1. 1

   System Voltage Test: Check the battery voltage with the engine off, and then with the engine running. If the running voltage is excessively high (e.g., >15V on a 12V system), the alternator/voltage regulator is overcharging the system.

2. 2

   Harness Inspection: Inspect the wiring harness leading to the BCM for chafing, melted insulation, or shorts to battery positive (B+).

3. 3

   Connector Check: Disconnect the BCM and inspect the pins for corrosion, moisture, or bent terminals that could cause bridging between power circuits.

4. 4

   Pin Voltage Verification: Measure the voltage directly at the BCM power supply pins for circuit 'B'. If the voltage at the pin is normal but the BCM still reports an 'out of range - high' condition, the BCM has an internal fault.

1. 1

   Safeguard the System

   Turn off the ignition and disconnect the battery ground cable to prevent electrical spikes.

2. 2

   Test the Charging System

   If the initial diagnostic checks revealed an overcharging alternator, replace the alternator or voltage regulator. Clear the codes and test run the machine. If the code does not return, the repair is complete.

3. 3

   Inspect and Repair Wiring

   Locate the BCM (usually located in the cab/console area). Disconnect the harnesses. If a short to B+ was found in the high-power "B" supply wire during diagnostics, repair the damaged section of the wiring harness using OEM-approved splicing methods.

4. 4

   Replace the BCM (if necessary)

   If the alternator is charging normally and the wiring is intact, the BCM's internal voltage monitor has failed.

5. 5

   Module Programming

   Install the new BCM. A newly installed BCM will be blank or have base software. You must connect the Case IH Electronic Service Tool (EST) to flash the correct BCM software and configure the machine's specific options (e.g., lighting configurations, installed alarms).