Case IH 56112 – Transmission Controller (TCU): Trans Controller Failure -- Internal short in the 1M Valve Coil circuit.

The transmission controller has commanded the 1M valve coil driver to the "OFF" position, but it still senses current flowing through the driver. This indicates that either the 1M clutch solenoid circuit is shorted to a 12V power source, or the 1M valve coil driver inside the transmission controller has suffered an internal failure.

• STX Steiger
• Case IH Puma Series
• Case IH Steiger Series
• STX models
• Case IH MX Magnum Series
• Case IH TG Series
• Case IH Quadtrac Series

1. 1

   Inspect the transmission wiring harness between the transmission controller and the 1M clutch solenoid for chafed wires, melted insulation, or pinched areas that could cause a short to a 12V power source.

2. 2

   Disconnect the harness at the 1M clutch solenoid and at the transmission controller. Use a multimeter to check for continuity to power (12V) on the 1M signal wire.

3. 3

   Test the resistance of the 1M clutch solenoid coil to ensure it is not internally shorted.

4. 4

   If the wiring harness and the solenoid both test good (no shorts to power found in the harness), verify that the 1M valve coil driver inside the transmission controller has failed.

1. 1

   Power Down

   Turn off the tractor, engage the parking brake, and disconnect the negative battery cable.

2. 2

   Resolve Wiring/Solenoid Issues

   If your diagnostics revealed a shorted wire, repair the harness. If the 1M solenoid tested bad, locate the transmission control valve block, remove the retaining hardware for the 1M solenoid, and install a replacement.

3. 3

   Replace the Transmission Controller

   If the controller's internal driver is the culprit: Locate the Transmission Controller, carefully disconnect the multi-pin harness connectors, unbolt and remove the faulty controller, install the new transmission controller and securely reconnect the harnesses.

4. 4

   Reassemble and Power Up

   Reconnect the battery cable and turn the key to the ON position.

5. 5

   Transmission Calibration

   Whenever a transmission controller or clutch solenoid is replaced, the transmission must be recalibrated. Bring the tractor's transmission fluid up to operating temperature, access the "TRANS SETUP" menu on the tractor's display, and follow the on-screen prompts to run the automated calibration procedure.

6. 6

   Clear Codes

   Clear the stored 56112 fault code from the system and test drive the tractor to ensure all forward and reverse gears engage properly.