Case IH 520526-04 - ITBV – ITBV (Intelligent Trailer Brake Valve): Outlet valve voltage low

The controller has detected a short circuit to ground on the relevant solenoid valve/actuator circuit. When this occurs, the trailer ABS/brake functions may be partly switched off, and a yellow driver warning is triggered.

• MAGNUM AFS Connect
• Magnum 180
• Magnum 200
• Magnum 220
• Magnum 240
• Magnum 250
• Magnum 280
• Magnum 295
• Magnum 310
• Magnum 340
• Magnum 380
• Puma 140
• Puma 150
• Puma 165
• Puma 175
• Puma 200 CVX
• Maxxum 145
• Maxxum 150 CVXDrive

1. 1

   Disconnect the ECU harness from the modulator valve and check the harness by itself for any shorts to battery or ground (there should be no continuity to ground)

2. 2

   Measure the resistance at the outlet valve pin to ground (should be between 4.0 and 9.0 ohms for a 12V system)

3. 3

   Measure the resistance at the ECU harness pins with the modulator valve connected (should read 4.0 to 9.0 ohms, with no more than a 1 ohm difference from the direct valve measurement)

1. 1

   Locate ITBV assembly

   Turn off the machine and locate the Intelligent Trailer Brake Valve (ITBV) assembly.

2. 2

   Disconnect electrical connector

   Disconnect the electrical connector to the ITBV outlet valve solenoid.

3. 3

   Perform resistance checks

   Perform the diagnostic resistance checks outlined above.

4. 4

   Repair wiring harness

   If the harness shows continuity to ground while disconnected from the valve, locate and repair the chafed/shorted section of the trailer brake wiring harness.

5. 5

   Replace pneumatic trailer brake valve

   If the harness tests good but the valve solenoid reads outside the 4.0-9.0 ohm specification (indicating an internal short circuit), the pneumatic trailer brake valve must be replaced.

6. 6

   Remove old valve

   To replace the valve, relieve system air/hydraulic pressure, disconnect the pneumatic/hydraulic lines (such as the ITBV to Solenoid Valve tube), and unbolt the valve assembly.

7. 7

   Install new valve

   Install the new ITBV valve, reconnect the lines and electrical harness, and clear the fault codes.

8. 8

   Test brake system

   Test the tractor and trailer brake system for proper operation and ensure the yellow driver warning does not return.