Case IH 12063 – STEERING: Communications Lost with Data Bus and ALL other controllers

The module has completely lost its connection to the tractor's Controller Area Network (CAN bus) and can no longer broadcast or receive messages from the rest of the vehicle's network.

• STX Steiger
• STX-275
• STX 350
• STX 400
• STX 450
• STX 500
• STX 550
• STX 600

1. 1

   Check battery voltage to ensure it does not drop below 11.5 volts during cranking or operation, and verify the alternator is charging properly.

2. 2

   Inspect the CAN bus wiring harness (specifically the yellow and green data wires) for chafing, cuts, or corrosion.

3. 3

   Check the CAN bus termination resistors, as older active terminators are highly prone to failure due to cracked solder joints.

4. 4

   Inspect the steering controller connectors for moisture, aging, or loose pins.

1. 1

   Disconnect Power

   Disconnect the battery cables and clean the terminals to ensure a solid power supply and prevent shorts during repair.

2. 2

   Inspect and Repair Terminators

   Locate the CAN bus active terminators. Peel back the rubber housing to inspect the circuit board and solder bad joints back together, or replace the failure-prone active terminators with updated OEM passive terminators.

3. 3

   Harness Repair

   If chafed or cut wires are found on the CAN bus harness during the diagnostic phase, splice and seal the wires using OEM-approved CAN bus wiring repair connectors.

4. 4

   Controller Replacement

   If the wiring, voltage, and terminators are all functioning correctly (e.g., data bus shows ~2.4 to 2.5 volts on the yellow/green wires) but the steering controller remains offline, the controller itself has likely suffered an internal failure and must be replaced.

5. 5

   Clear Codes

   Reconnect the battery. Use the tractor's display or a Case IH Electronic Service Tool (EST) to clear the stored fault codes and verify that the steering controller is back online.