Case IH 1056-01 - ITBV – ITBV: Trailer brake control line pressure disagreement - pressure low (while driving)

A plausibility check failure where the actual pneumatic pressure measured on the trailer brake control line is lower than the demanded/commanded pressure while the tractor is in motion (driving above a specific speed threshold), pointing to an inability of the system to maintain or reach the required braking pressure for the trailer due to a pneumatic leak, a blockage, or a sensor/valve failure.

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

1. 1

   Verify the air supply pressure and minimum pressure to ensure the tractor's main air system is feeding the ITBV correctly.

2. 2

   Check the pneumatic supply lines routing to the trailer control valve for blockages, severe contamination, or kinks.

3. 3

   Run a leak down test to check for air leaks at the air inlet module, the outlet, and along the pneumatic brake control lines.

4. 4

   Verify the wiring harness between the ITBV ECU and the pressure sensors for open circuits or shorts to power/ground.

1. 1

   Safely park the tractor and drain the pneumatic air reservoirs before opening the brake system.

2. 2

   Inspect all pneumatic lines connected to the ITBV.

   Repair or replace any broken, leaking, or kinked control lines.

3. 3

   Determine if the issue is internal to the valve or its integrated pressure sensor.

   This is likely if the lines are intact and hold pressure, but the system still registers low pressure on the control line.

4. 4

   Replace the Intelligent Trailer Brake Valve (ITBV) / ECU assembly.

5. 5

   Re-pressurize the system and check for leaks at the new fittings.

6. 6

   Connect a diagnostic PC/tool to delete the inactive fault codes.

7. 7

   Perform a test drive above the speed threshold to ensure the plausibility check passes and the fault does not return.