Case IH 520576-05 - BCM – BCM: Battery isolator set - open circuit

The control module has detected a break in continuity, a disconnected harness, or a blown fuse within the electronic battery isolator control circuit. The system cannot detect the required voltage/current returning from the isolator relay or switch.

• MAGNUM AFS Connect
• Magnum AFS Connect Series
• Steiger AFS Connect series
• Puma
• Maxxum

1. 1

   Locate the electronic battery isolator switch/relay and inspect the electrical connector for disconnected pins, corrosion, or physical damage.

2. 2

   Measure the resistance of the wiring harness between the BCM and the battery isolator (should be less than 5 ohms), gently shaking it to check for intermittent breaks.

3. 3

   Disconnect the battery isolator and check the associated fuses (5-Amp mini fuse) and relays in the power distribution box.

1. 1

   Power Down

   Turn off the tractor and ensure the key is removed.

2. 2

   Disconnect

   Press the upper side of the battery isolator switch to manually disconnect the battery (if possible) to ensure safety. Disconnect the battery isolator switch electrical connector.

3. 3

   Repair Wiring (If Applicable)

   If the continuity test revealed a broken wire, repair the break in the harness or replace the damaged connector pins.

4. 4

   Replace Component

   If the wiring, fuses, and relays are intact, the internal coil of the electronic battery isolator switch/relay has likely failed open. Unbolt the faulty battery isolator and install the replacement part.

5. 5

   Reassembly

   Reconnect the electrical harness to the new isolator.

6. 6

   Clear Codes

   Turn the battery power back on, cycle the key, and use the diagnostic tool to clear the BCM fault codes. Verify that the 520576-05 code does not return.