Case IH 3683-19 - UCM – UCM: Vehicle controller communication fault with steering wheel angle sensor

The control module has lost CAN bus communication with the steering wheel angle sensor, or the sensor is detecting an abnormal voltage state (open circuit, short to ground, or short to power) preventing it from transmitting its position data.

• MAGNUM AFS Connect
• Case IH Magnum AFS Connect
• Case IH 2000 Series Planters
• 2150S
• 2160
• Steiger series

1. 1

   Visually inspect if the steering wheel angle sensor is physically connected.

2. 2

   Inspect the wiring harness connecting the steering wheel angle sensor to the UCM for an open circuit, chafed wires, or a short to ground/power.

3. 3

   Test the CAN-High and CAN-Low communication lines between the sensor and the UCM for proper resistance and continuity.

4. 4

   Check for excessive physical play in the steering angle sensor linkage or the front axle bearings, which can cause erratic readings.

5. 5

   Verify if the steering wheels are physically centered. Manually center the steering system to see if communication or calibration can be restored.

1. 1

   Secure the Machine

   Park the machine on a level surface, turn off the engine, and manually center the steering system.

2. 2

   Inspect and Clean Connections

   Locate the steering wheel angle sensor (typically mounted on the steering axle or steering column depending on the machine). Disconnect the sensor, clean the pins with electrical contact cleaner, and reconnect it securely.

3. 3

   Repair Wiring

   If the multimeter tests during diagnostics revealed a short or open circuit in the harness, repair or replace the damaged section of the wiring harness.

4. 4

   Replace the Sensor

   If the wiring is intact and the UCM is outputting the correct reference voltage but communication is still lost, the sensor has suffered an internal device failure. Remove the mounting hardware, disconnect the linkage, and install a new steering wheel angle sensor.

5. 5

   Recalibrate the Steering System

   After replacing the sensor or repairing the wiring, you must perform a steering wheel angle sensor calibration via the Pro 1200 display or diagnostic tool. Ensure the front wheels are exactly in the center position during this adjustment, or the calibration will fail and throw a secondary error.

6. 6

   Clear Codes

   Clear the 3683-19 fault code from the UCM and test-drive the machine to ensure the steering tracks correctly and the code does not return.