Case IH 2904 – Transmission Controller: Brake pressure transducer – open circuit or short circuit to ground

The control module is not receiving a valid voltage signal from the service brake pressure transducer. The system is detecting either an "open circuit" (a broken wire, disconnected plug, or failed internal sensor element) or a "short to ground" (the signal wire is chafed and touching the chassis, pulling the voltage to 0V). Because of this, the machine's computer cannot monitor the hydraulic pressure being applied to the service brakes.

• Steiger T4B
• Case IH Puma Series (165, 180, 195, 210, 225 CVX)
• Case IH Maxxum Series (e.g., Maxxum 140)
• Case IH Magnum Series

1. 1

   Visually inspect the wiring harness leading to the brake pressure transducer on the brake manifold for chafed wires (short to ground) or a loose/corroded connector (open circuit).

2. 2

   Disconnect the sensor, turn the key ON, and use a multimeter to verify that the sensor is receiving its 5V DC reference power supply and has a good ground at the harness connector.

3. 3

   Perform a continuity and resistance test on the signal wire from the sensor connector back to the Transmission Controller pins to ensure there is no open circuit (resistance should be less than 10 ohms) or short to the chassis ground.

1. 1

   Depressurize the System

   Ensure the machine is turned off, parked on a level surface, and the wheels are chocked. Pump the brake pedals to relieve any residual hydraulic pressure in the brake manifold.

2. 2

   Disconnect the Sensor

   Locate the brake pressure transducer on the brake valve/manifold block and disconnect its electrical connector.

3. 3

   Remove the Transducer

   Unscrew the transducer from the manifold. Note: Have a catch pan and shop towels ready, as a small amount of hydraulic oil will leak out of the fitting when the transducer is removed.

4. 4

   Install the New Part

   Thread the new OEM brake pressure transducer into the manifold and tighten to the specified torque.

5. 5

   Reconnect and Clear

   Reconnect the electrical harness. Power on the machine, clear the stored fault codes via the diagnostic display, and test the brake pedals to ensure the code does not return and pressure is reading correctly.