Case IH 14091 – Transmission Control Unit (TCU): Transmission Output Speed Sensor Short to Vcc or Open Circuit

The system has detected that the Transmission Output Speed Sensor's circuit has a short to Vcc (high voltage/power supply) or an open circuit, meaning the controller is either receiving a constant high voltage signal or no signal at all.

• Maxxum
• Farmall
• MXU series
• Puma
• Magnum
• Steiger

1. 1

   Check ADIC / Instrument Panel Configuration (especially if recently replaced, as it can falsely trigger on 16x16 tractors if configured for 24x24)

2. 2

   Inspect the transmission output speed sensor connector for corrosion, backed-out pins, or physical damage

3. 3

   Use a multimeter to check the sensor wiring harness for an open circuit or a short to a 5V/12V power source (Vcc) between the sensor and the transmission controller

1. 1

   Verify Module Configuration

   If the instrument cluster was recently replaced, connect the dealer diagnostic laptop. Reconfigure the ADIC panel to the correct transmission type (e.g., changing it from 24x24 to 16x16) and recalibrate the transmission. If this resolves the code, no parts are needed.

2. 2

   Test the Harness

   If the configuration is correct, disconnect the transmission output speed sensor. Turn the key ON and probe the signal wire on the harness side to ensure it is not shorted to voltage. Test for continuity back to the transmission controller to rule out an open circuit.

3. 3

   Repair Wiring

   If a short or open circuit is found in the harness, repair or replace the damaged wiring section.

4. 4

   Replace the Sensor

   If the wiring harness tests good and the module configuration is correct, the sensor has failed internally. Remove the retaining bolt, pull the old transmission output speed sensor from the transmission housing, and install the new sensor.

5. 5

   Recalibrate

   Clear the fault codes. Depending on the model, perform a transmission calibration procedure to ensure the controller recognizes the new sensor inputs.