Case IH 627-24 - ITBV – ITBV: 12V supply voltage low

The control module has detected that its 12V unswitched battery supply voltage has dropped below the acceptable operating threshold (often falling below 6.2V momentarily) or is missing entirely. This prevents the module from functioning correctly and can disable the trailer braking system.

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

1. 1

   Verify that the tractor's batteries are fully charged and the alternator is outputting proper voltage, as low system voltage during cranking can trigger this code.

2. 2

   Check the Power Distribution Module (PDM) for blown 10A, 15A, or 30A mini fuses related to the ITBV unswitched power supply.

3. 3

   Inspect the wiring harness leading to the ITBV valve (connector X-386F) for corrosion, backed-out pins, or wire chafing along the chassis.

4. 4

   Disconnect the ITBV connector and perform a voltage drop test on both the power and ground circuits with the key ON to ensure there is no high resistance.

1. 1

   Power Down

   Turn the key OFF and disconnect the battery negative terminal to prevent electrical shorts during repair.

2. 2

   Resolve Power Supply Issue

   If a fuse is blown, replace it with the exact OEM amperage rating. If wiring is damaged or corroded, splice in a new section of wire using weather-sealed heat shrink connectors, or replace the damaged connector pigtail.

3. 3

   Component Replacement (If Internal Short)

   If the wiring and fuses are perfectly intact but the ITBV module is internally shorted (pulling the 12V reference down), the ITBV valve assembly must be replaced. Relieve all pneumatic/hydraulic pressure from the trailer brake lines. Disconnect the air hoses and hydraulic lines from the ITBV block. Unbolt the ITBV valve from its mounting bracket. Install the new ITBV valve, reconnect all lines, and plug in the electrical harness.

4. 4

   Software Calibration

   Note that replacing the ITBV may require a software parameterization/calibration routine using the Case IH Electronic Service Tool (EST) to ensure the new valve communicates properly with the tractor's CAN bus.

5. 5

   Test

   Reconnect the battery, clear the inactive fault codes, and perform a functional test of the trailer brakes.