Case IH 15238 – CCM (Central Control Module): Vehicle speed sensor message (from TCU) offline.

This indicates a communication failure where the expected vehicle speed data message broadcasted by the Transmission Control Unit (TCU) is not being received over the CAN bus network. It typically points to a network communication issue, a failed TCU, or a failed vehicle speed sensor that is causing the TCU to stop broadcasting the speed message.

• Steiger T4B
• MAXXUM T4E
• VESTRUM CVX
• Farmall 40
• Farmall 45
• Farmall 50
• Puma CVT
• Optum CVT

1. 1

   Verify that the TCU is powered up and communicating with the rest of the tractor's network. Check for other offline codes (e.g., 15242 Steering control message offline) which would indicate a broader CAN bus or TCU power failure.

2. 2

   Inspect the wiring harness between the Vehicle Speed Sensor and the TCU, as well as the CAN bus lines between the TCU and the CCM. Look for chafed wires, loose pins, or corrosion in the connectors.

3. 3

   Test the inductive vehicle speed sensor at the transmission housing for proper resistance and voltage signal output when the wheels are turning.

1. 1

   Power Down

   Turn off the tractor, remove the key, and disconnect the negative battery cable to prevent electrical shorts.

2. 2

   Locate the Sensor

   Locate the vehicle speed sensor, which is mounted on the side of the CVT transmission housing.

3. 3

   Disconnect Wiring

   Carefully unplug the electrical connector from the speed sensor. Inspect the harness-side connector for dirt or moisture and clean if necessary.

4. 4

   Remove the Sensor

   Remove the retaining bolt or fixing pin holding the sensor in place. Carefully pull the old inductive speed sensor out of the transmission case.

5. 5

   Install the New Sensor

   Lubricate the O-ring on the new sensor with a small amount of clean transmission fluid. Insert the new sensor into the housing and secure it with the retaining bolt/pin.

6. 6

   Reconnect

   Plug the electrical connector back into the sensor until it clicks.

7. 7

   Clear Codes and Test

   Reconnect the battery. Use a diagnostic tool to clear the 15238 fault code. Test drive the tractor to ensure the speedometer registers correctly and the fault code does not return.