Case IH t45 – Engine Control Module (ECM): CAN CCVSS Message, Data Valid But Below Normal Range

This code indicates that the vehicle speed data being sent from the central controller to the engine control module is valid, but the frequency/value falls below the normal expected operating range. This typically points to a failing inductive speed sensor, a poor wiring connection, or a communication timeout on the CAN bus.

• MXM
• MXM120
• MXM130
• MXM140
• MXM155
• MXM175
• MXM190
• Maxxum
• Puma
• Magnum
• TM Series
• TM115
• TM190
• TS Series
• T6 Series
• T7 Series

1. 1

   Visually inspect the vehicle speed sensor (VSS) on the transmission housing cover, flywheel bell housing, or rear axle for physical damage or heavy debris buildup.

2. 2

   Disconnect the 2-pin connector at the sensor and inspect for moisture, corrosion, or pushed-back pins.

3. 3

   Check wiring continuity for the CAN bus and direct sensor wiring between the sensor, the Central Controller (XCM), and the Engine Control Module (ECM), looking for shorts to ground or open circuits.

4. 4

   Test the VSS output using a multimeter or oscilloscope to verify it produces a proper digital square-wave frequency when the wheels/transmission are in motion.

5. 5

   Check for related fault codes like t46 (Data Incorrect) or t47 (Data Valid But Above Normal Range) to isolate if the sensor is completely dead or reading erratically.

1. 1

   Power Down

   Turn off the tractor and disconnect the battery to protect the ECU and CAN bus network.

2. 2

   Access the Sensor

   Clean the area around the transmission housing/rear axle where the speed sensor is mounted to prevent dirt from falling into the transmission.

3. 3

   Remove the Sensor

   Unplug the 2-pin wiring harness. Unthread the faulty stainless-steel barrel sensor from the housing.

4. 4

   Install the New Sensor

   Thread the new OEM inductive speed sensor into the housing. (Note: Refer to the specific model's service manual for exact depth/air-gap adjustment if the sensor uses a locknut, though many are fixed-depth).

5. 5

   Reconnect

   Plug the 2-pin connector back in, ensuring the weather seal clicks into place. Secure any loose wiring with zip ties to prevent chafing against the chassis.

6. 6

   Clear Codes

   Reconnect the battery. Turn the key to the ON position and use your diagnostic service tool to clear the t45 / 3658-1 fault code from the ECM.

7. 7

   Test Drive

   Operate the tractor to verify that the digital dashboard speedometer reads accurately and that the fault code does not return.