Case IH 14021 – Tractor Control Unit (TCU): Secondary steering is present and no CAN messages are received

There is a loss of Controller Area Network (CAN) bus communication between the secondary (auxiliary) steering controller and the Tractor Control Unit (TCU). The TCU is recognizing that the tractor is equipped with a secondary steering system, but it is not receiving the expected data broadcasts from the secondary steering module.

• Steiger T4B
• Case IH STX Steiger Series (Models 350, 400, 450, 500, 550, 600)
• Case IH Magnum Series (Models 250, 280, 310, 340, 380, including Rowtrac variants)

1. 1

   Connector Inspection: Check all Tractor Control Unit (TCU) and secondary steering controller connectors. Ensure the connectors are fully connected, not damaged, the pins are in the correct position, and that the pin fit is tight.

2. 2

   Wiring Harness Check: Inspect the CAN bus wiring between the secondary steering controller and the TCU for continuity, open circuits, or short circuits (to ground or +12V).

3. 3

   Power and Ground: Verify that the secondary steering controller is receiving proper operating voltage and has a clean ground connection.

1. 1

   Safely shut down the machine

   Turn off the engine, engage the parking brake, and disconnect battery power to prevent electrical shorts during testing.

2. 2

   Locate the modules

   Locate the Tractor Control Unit (TCU) and the secondary steering controller on the machine.

3. 3

   Inspect and clean connectors

   Disconnect the wiring harness at both the TCU and the secondary steering controller. Inspect for pushed-out pins, corrosion, or moisture. Clean and reseat the connectors tightly. Repair or replace connector pins as required.

4. 4

   Test the CAN circuit

   Using a multimeter, perform a continuity test on the CAN High and CAN Low wires between the two modules. If an open circuit or short is found, repair or replace the affected section of the wiring harness.

5. 5

   Software Configuration

   If the wiring and connectors are physically okay, connect the Case IH Electronic Service Tool (EST). Download the correct level of software and reconfigure the control unit/valves.

6. 6

   Clear and Retest

   Clear the fault codes using the EST. Cycle the key and operate the steering system to see if code 14021 returns.

7. 7

   Module Replacement

   If the wiring is intact, software is up to date, and the code persists, the secondary steering controller (or in rare cases, the TCU) has internally failed and must be replaced.