Case IH A-G-635 - Display – Display / AFS Module: No communication with the steering controller

This is a CAN (Controller Area Network) bus communication error indicating that the Display module is failing to receive expected data packets from the target controller (either the Primary Display Unit itself in a multi-display setup, or the Steering/Guidance Controller).

• MAGNUM AFS Connect
• STEIGER AFS Connect
• Puma
• Optum

1. 1

   Verify power and ground by checking the fuses supplying the Cab Electronics, the Primary Display Unit (PDU), and the Steering Controller

2. 2

   Check for accompanying 'No Communication' codes to determine if the entire CAN bus is down or if the issue is isolated to the display/steering node

3. 3

   Perform a CAN bus resistance test at the diagnostic port with the key off and battery disconnected (should read approximately 60 ohms; 120 ohms indicates an open circuit or missing resistor)

4. 4

   Inspect connectors at the back of the AFS display and the steering controller for moisture, corrosion, or pushed-out pins

1. 1

   Power Down

   Turn off the ignition and disconnect the negative battery cable to prevent electrical spikes during testing.

2. 2

   Access the Harness

   Remove the interior trim panels necessary to access the rear of the AFS Display and the routing to the steering controller/PDU.

3. 3

   Isolate the Circuit

   Disconnect the main harness from the display.

4. 4

   Test Wiring Continuity

   Using a digital multimeter, perform a continuity test on the CAN High and CAN Low wires from the display connector to the target controller. Repair any breaks or chafed wires in the harness.

5. 5

   Check Terminating Resistors

   Ensure the active terminators on the CAN network are functioning properly (often located at the ends of the bus line).

6. 6

   Re-seat and Test

   Apply dielectric grease to the connector seals, firmly re-seat the connections, and reconnect the battery.

7. 7

   Software/Hardware Resolution

   Turn the key to the ON position. If the code changes from 'Active' to 'Inactive,' clear the code. If the code remains active and all wiring/voltages test perfectly, the Display or the Steering Controller has an internal hardware failure and must be replaced or sent out for IPC-certified CAN rework.