Case IH 15233 – TCU (Transmission Control Unit) or CCM & APH (Chassis Control Module / Auto Pilot/Guidance): Steering wheel sensor communication lost

CAN bus communications between the steering wheel position sensor (also known as the steering angle sensor), the electronic steering valve, and the control unit have been interrupted. The system is no longer receiving valid position or velocity data from the steering wheel sensor, which disables auto-guidance and electronic steering features.

• Steiger T4B
• Farmall 40 CVT
• Farmall 45 CVT
• Farmall 50 CVT
• Maxxum (100-140)
• Profi (4110-6140)
• Steiger
• Magnum
• 5088
• 6088
• 7010
• 7120
• 7230
• 8010
• 8120
• 8230
• 9010
• 9120
• 9230
• AFX8010
• Patriot 3230
• Patriot 3320
• Patriot 3330
• Patriot 4420
• Patriot 4430
• Patriot 4440

1. 1

   Check for related codes that might isolate the issue, such as 15234 (Steering wheel sensor offline) or 15235 (Steering wheel sensor invalid velocity or position value).

2. 2

   Visually inspect the CAN bus wiring harness running between the steering wheel position sensor, the electronic steering valve, and the TCU for chafed wires, pinched harnesses, or rodent damage.

3. 3

   Disconnect the harness at the steering wheel sensor and the TCU to inspect the pins for corrosion, moisture, or pushed-out terminals.

4. 4

   Verify the steering wheel sensor is receiving proper operating voltage (typically 9-32 VDC) and has a solid ground connection.

5. 5

   Use a multimeter to check the resistance across the CAN High and CAN Low pins to ensure the CAN bus network is intact (should typically read approximately 60 ohms).

1. 1

   Disconnect Power

   Turn off the machine and disconnect the negative battery cable to prevent electrical shorts and accidental airbag/steering system deployment.

2. 2

   Access the Sensor

   Remove the steering wheel and the plastic steering column shrouds to access the steering wheel position sensor (SASA sensor), which is mounted between the steering column and the steering unit.

3. 3

   Harness Repair

   If the diagnostic checks revealed a broken wire or damaged connector on the CAN bus line, splice and repair the wiring using OEM-approved weatherproof connectors.

4. 4

   Replace the Sensor

   If the wiring and voltages are correct but communication is still lost, the sensor has failed internally. Disconnect the sensor's electrical connector, unbolt the sensor from the column, and install the new unit.

5. 5

   Reassembly

   Reinstall the steering column shrouds and the steering wheel. Reconnect the battery.

6. 6

   Calibration

   Connect the Case IH diagnostic tool (EST). Clear the inactive fault codes and perform a steering angle sensor calibration to teach the TCU the new sensor's zero-degree (straight ahead) index point.