Case IH 1067-03 - ITBV – ITBV: Trailer brake controller service brake sensor voltage high

The control module is receiving a voltage signal from the sensor that is above the normal operating range. This is typically caused by a short to power (the signal wire touching a 5V or 12V source), a broken ground wire, or an internal failure of the sensor itself.

• MAGNUM AFS Connect
• Puma
• Maxxum
• Magnum
• Farmall
• Farmall 105U/115U
• Puma 145-225
• MXM155

1. 1

   Inspect the wiring harness between the brake pressure sensor and the ITBV module for chafed wires, pinched lines, or areas where insulation has rubbed away causing a short to power.

2. 2

   Check the sensor connector for corrosion, moisture, or loose terminals that could cause a bad connection.

3. 3

   Test the ground circuit to verify the ground pin at the sensor connector has continuity to the chassis ground (a broken ground causes signal voltage to float high).

4. 4

   Isolate the sensor to determine if it has failed internally and is shorting the reference voltage to the signal return.

1. 1

   Power Down

   Turn off the tractor, remove the key, and disconnect the battery to prevent electrical spikes.

2. 2

   Locate the Sensor

   Find the service brake pressure sensor. Depending on your exact model, it will be mounted on the trailer brake valve block (often near the rear axle) or directly on the air/hydraulic brake lines near the firewall.

3. 3

   Repair Wiring

   If your diagnostic checks revealed chafed wires or a broken ground, splice and repair the damaged section using heat-shrink connectors. Apply dielectric grease to the connector to prevent future moisture intrusion.

4. 4

   Replace the Sensor

   If the wiring is intact, unscrew the faulty brake pressure sensor from the valve block/line. Install the new sensor and tighten it to OEM torque specifications.

5. 5

   Calibrate the System

   Reconnect the battery and clear the inactive fault codes using a diagnostic tool (like the CNH EST). You may need to perform a brake pedal/sensor calibration procedure (pressing and holding the brake pedal firmly while the system is charged) so the ITBV can learn the new sensor's zero-pressure voltage.