Case IH 520528-04 - ITBV – CCM (Chassis Control Module) or APH (Advanced Proportional Hydraulics): ITBV (Intelligent Trailer Brake Valve) - Voltage Below Normal, or Shorted to Low Source

The control module has detected that the electrical circuit supplying the Intelligent Trailer Brake Valve has a low voltage condition, most likely caused by a short to ground in the wiring harness or an internal short within the valve's solenoid coil.

• MAGNUM AFS Connect
• Maxxum
• Maxxum 145 Multicontroller ActiveDrive 8
• Puma
• Magnum
• T6
• T6.160
• T7
• T7.190
• T7.210
• T8
• T8.410

1. 1

   Inspect the wiring harness from the Chassis Control Module to the ITBV for chafed wires rubbing against the chassis that could cause a short to ground.

2. 2

   Inspect the ITBV electrical connector (X-386F) for water ingress, corrosion, or melted pins.

3. 3

   Disconnect the ITBV and use a multimeter to verify that the module is sending the correct reference voltage to the valve and that the ground circuit is intact.

4. 4

   Measure the resistance across the pins of the ITBV solenoid coil. A reading near 0 ohms indicates the coil is internally shorted and the valve must be replaced.

1. 1

   Depressurize the System

   Turn off the tractor, disconnect the battery to prevent electrical spikes, and safely bleed all compressed air from the tractor's air reservoirs to prevent injury when removing the pneumatic valve.

2. 2

   Locate the ITBV

   Locate the Intelligent Trailer Brake Valve assembly on the rear chassis/pneumatic block of the tractor.

3. 3

   Disconnect Electricals

   Unplug the X-386F electrical connector from the ITBV. If the connector is damaged, splice in a new pigtail/connector.

4. 4

   Remove the Valve

   Mark the pneumatic air lines for reassembly, then disconnect them from the inlet and outlet ports of the valve. Remove the mounting hardware securing the valve to the bracket.

5. 5

   Install the New Valve

   Mount the replacement ITBV and securely reconnect the pneumatic lines.

6. 6

   Reconnect and Test

   Plug in the electrical connector. Reconnect the battery, start the tractor to build air pressure, and check for air leaks. Clear the 520528-04 fault code using a diagnostic service tool and perform a functional test of the trailer brakes.