Case IH 6584-04 - DEC – Transmission Control Unit (TCU) or Vehicle Control Unit (VCU): Transmission Hydrostatic Loop 2 Pressure - Voltage Below Normal, or Shorted to Low Source

The control module is receiving a voltage signal from the hydrostatic loop 2 pressure sensor that is below the minimum acceptable threshold (typically below 0.5V on a 5V circuit). This indicates that the sensor has failed internally, the signal wire is shorted to ground, or there is a complete loss of the 5V reference supply to that specific sensor.

• MAGNUM AFS Connect
• Case IH Magnum Series (235, 250, 280, 310, 340, 380)
• Case IH Steiger / Quadtrac / Rowtrac Series (370, 420, 450, 470, 500, 540, 580, 620)
• Case IH Puma Series
• Case IH Maxxum Series

1. 1

   Locate the Hydrostatic Loop 2 (Pressure B) sensor on the transmission valve block and visually inspect the wiring harness for chafing, melted insulation, or pinch points that could cause a short to ground.

2. 2

   Disconnect the sensor and check the weather-pack connector for water intrusion, bent pins, or corrosion.

3. 3

   Turn the key to the ON position (engine off) and use a multimeter to measure the voltage at the sensor connector's supply pin. It should receive a regulated 5V DC reference from the ECU.

4. 4

   Check the continuity of the signal wire back to the transmission controller. Test the signal wire for a short to ground (resistance to chassis ground should be infinite/open).

5. 5

   If the 5V supply and ground are good, and the signal wire is not shorted to the chassis, verify if the sensor itself has an internal short and requires replacement.

1. 1

   Safety First

   Park the machine on a level surface, engage the parking brake, turn off the engine, and remove the key.

2. 2

   Relieve Pressure

   Relieve any residual hydraulic/hydrostatic pressure in the transmission system as per the operator's manual to prevent fluid spray.

3. 3

   Remove the Sensor

   Disconnect the electrical harness from the faulty Pressure B sensor. Use the appropriate wrench to unthread the sensor from the hydrostatic loop port.

4. 4

   Install the New Sensor

   Thread the new OEM pressure transducer into the port. Tighten to the torque specification outlined in the service manual (do not overtighten, as this can damage the transducer diaphragm).

5. 5

   Reconnect

   Plug the electrical connector back in, ensuring the locking tab clicks into place to maintain the weather seal.

6. 6

   Clear Codes

   Turn the key on. Use the CNH Electronic Service Tool (EST) or an equivalent diagnostic tool (like Jaltest) to clear the inactive 6584-04 fault code from the TCU memory.

7. 7

   Test Operation

   Start the tractor and observe the dashboard/AFS Pro display. Engage the transmission to build hydrostatic pressure and verify the code does not return.