Case IH 56117 – Transmission Controller (TCU / TRANS): Trans Controller Failure — Internal short in the 4R Valve Coil circuit

The transmission controller has commanded the 4R valve coil driver OFF, but it still senses current flowing through the driver. This specifically indicates an internal failure within the transmission controller itself (the internal driver for the 4R valve coil has failed).

• STX Steiger
• STX Steiger Series
• STX275
• STX325
• STX375
• STX425
• STX450
• STX480
• Puma Series
• MX Magnum Series

1. 1

   Verify the active fault code by entering the 'Trans View' mode on the cab display.

2. 2

   Inspect the wiring harness between the 4R clutch solenoid and the transmission controller for rubbed wires or areas where the harness might be shorted to a 12V power source.

3. 3

   Test the resistance of the 4R clutch solenoid coil to ensure it is not internally shorted. If the solenoid is shorted, replacing the controller without replacing the solenoid will instantly destroy the new controller.

1. 1

   Power Down

   Turn the key OFF and disconnect the tractor's battery to prevent electrical arcing.

2. 2

   Locate the Controller

   Access the Transmission Controller. On most STX and Magnum models, this is located underneath the fuse/relay panel in the cab or behind the right-hand console.

3. 3

   Remove the Failed Module

   Carefully disconnect the multi-pin wiring harness connectors from the controller. Remove the mounting hardware and extract the failed unit.

4. 4

   Install the New Module

   Mount the replacement transmission controller and securely reconnect the wiring harnesses.

5. 5

   Restore Power

   Reconnect the battery.

6. 6

   Clear Codes

   Turn the key ON, enter the Trans Setup menu using the PROG and DECR keys on the display, and clear the old fault codes.

7. 7

   Calibrate the Transmission

   Start the tractor and bring the transmission fluid up to operating temperature. Enter the Trans Setup Menu and initiate the calibration procedure. Follow the on-screen prompts (e.g., 'Pedal Dn', shifting to neutral, and increasing engine speed to 2000 RPM) to allow the controller to calibrate the fill times for the clutches and valves. Press the PROG key to exit and save the calibration once the display reads that the process is complete.