Case IH 2055 (191.02) - DEC – Transmission Control Unit (TCU): Wheel speed (transmission output speed) sensor – no signal

The controller is not receiving a valid frequency or voltage signal from the transmission output speed sensor. Without this data, the machine's computer cannot determine how fast the vehicle is moving, which can cause the transmission to default to a protective mode, shift erratically, or refuse to move.

• MAXXUM T4E
• VESTRUM CVX
• Magnum series
• Steiger series
• Puma series
• Farmall series
• Axial-Flow Combines

1. 1

   Visually inspect the transmission output speed sensor body and the wiring harness for physical damage, rubbing, or melting.

2. 2

   Disconnect the sensor connector (e.g., Connector X-309 or X555) and check for moisture, dirt, or corroded pins.

3. 3

   Use a multimeter to check for continuity, open circuits, or a short-to-ground on the wires running from the sensor connector back to the TCU.

4. 4

   Remove the sensor and inspect the magnetic tip. Clean off any metal shavings or heavy sludge from the transmission oil that may be blinding the sensor.

1. 1

   Preparation

   Park the machine on a level surface, engage the parking brake, turn off the engine, and disconnect the battery to prevent electrical shorts.

2. 2

   Locate the Sensor

   Locate the transmission output speed sensor on the exterior of the transmission housing (refer to your specific model's parts diagram for exact placement).

3. 3

   Removal

   Disconnect the electrical harness connector from the sensor. Remove the retaining bolt securing the sensor to the housing.

4. 4

   Extraction

   Carefully pull the sensor straight out of the transmission housing. Have a rag ready, as a small amount of transmission fluid may weep from the port.

5. 5

   Installation

   Lubricate the O-ring on the new sensor with clean transmission fluid. Insert the new sensor into the housing, ensuring it seats fully and squarely.

6. 6

   Secure

   Install and tighten the retaining bolt to the OEM torque specification.

7. 7

   Reconnect

   Reconnect the electrical harness, ensuring the locking tab clicks into place. Reconnect the battery.

8. 8

   Calibration/Testing

   Turn the key on and clear the inactive 2055 fault code via the cab monitor. Test drive the machine to verify that the speedometer registers correctly and the transmission shifts normally.