Case IH 14020 – Tractor Control Unit (TCU) or Engine Control Unit (ECU): Loss of CAN messages from the secondary steering controller

The main control module is no longer receiving the expected communication signals over the Controller Area Network (CAN) bus from the module responsible for the secondary/auxiliary steering system.

• Steiger T4B
• STX Steiger
• Quadtrac
• Steiger 350
• Steiger 400
• Steiger 450
• Steiger 500
• Steiger 550
• Steiger 600
• Quadtrac 450
• Quadtrac 500
• Quadtrac 550
• Quadtrac 600

1. 1

   Locate the wiring harness connecting the secondary steering controller to the main ECU/TCU.

2. 2

   Inspect the connectors at both the steering controller and the ECU. Ensure the connectors are fully seated, not damaged, and that the pins are in the correct position with a tight fit.

3. 3

   Check the CAN bus wiring harness for continuity between the secondary steering controller and the ECU.

4. 4

   Inspect for any shorts to ground, shorts to power, or open circuits in the communication lines.

1. 1

   Turn off the machine and disconnect the battery to ensure safety while working on the electrical system.

   Turn off the machine and disconnect the battery to ensure safety while working on the electrical system.

2. 2

   Disconnect the wiring harness connectors at the secondary steering controller and the ECU.

   Disconnect the wiring harness connectors at the secondary steering controller and the ECU.

3. 3

   If any pins are bent, corroded, or pushed back, repair or replace the connector terminals as required.

   If any pins are bent, corroded, or pushed back, repair or replace the connector terminals as required.

4. 4

   If the wiring harness fails the continuity test or shows physical damage (chafing, melting), repair the damaged section of the harness or replace the harness entirely.

   If the wiring harness fails the continuity test or shows physical damage (chafing, melting), repair the damaged section of the harness or replace the harness entirely.

5. 5

   Reconnect all connectors securely. Power the machine on and check if the fault code is still present.

   Reconnect all connectors securely. Power the machine on and check if the fault code is still present.

6. 6

   If the wiring and connectors are verified to be in good working condition but the fault code remains active, the secondary steering controller itself has failed internally and must be replaced.

   If the wiring and connectors are verified to be in good working condition but the fault code remains active, the secondary steering controller itself has failed internally and must be replaced.

7. 7

   Install the new secondary steering controller, clear the fault codes using an Electronic Service Tool (EST), and return the machine to operation to verify the repair.

   Install the new secondary steering controller, clear the fault codes using an Electronic Service Tool (EST), and return the machine to operation to verify the repair.