John Deere 002071.09 – SCU, ICU, ECU, SCO, ATC: CAN Bus Communication Failure

The system has detected a communication issue on the Controller Area Network (CAN bus). This fault code (SPN 2071, FMI 9) indicates an abnormal update rate, meaning a control unit is not receiving expected messages from the Chassis Control Unit (CCU), or the data is arriving too slowly. This signifies a problem with the communication between components or systems, typically caused by physical network infrastructure issues rather than a single mechanical failure.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 7715
• 7815
• 7720
• 7820
• 7920
• 7630
• 7730
• 7830
• 7930
• 8130
• 8230
• 8330
• 8430
• 8530
• 8RX 410
• 9230
• 9330
• 9430
• 9530
• 9630

1. 1

   Restart the machine by cycling the key switch off, waiting, and restarting to see if the intermittent communication error resets

2. 2

   Check fuses based on the controller logging the fault: F6 (ATC Message Missing), F6 and F35 (ICU reporting CCU Message Missing), F30 (SCU Message Missing), F22 (CAB Message Missing), and F24 (ECU Message Missing)

3. 3

   Inspect the batteries and alternator to ensure connections are clean and secure

4. 4

   Check the CAN bus harness and connectors for visible signs of damage, corrosion, or loose connections, paying special attention to the rear ISO connector

5. 5

   Examine the wiring and connectors for the Chassis Control Unit (CCU) and the reporting module (e.g., the Roof Module/ATC)

1. 1

   Perform CAN Bus Resistance Test

   Turn the machine's power completely off. Disconnect a connector on the CAN bus and measure resistance between CAN High (Yellow wire) and CAN Low (Green wire). The expected result is approximately 60 ohms. A reading of 120 ohms indicates a missing or failed terminating resistor, while significantly less than 60 ohms suggests a short circuit or faulty module.

2. 2

   Perform CAN Bus Voltage Test

   Turn the machine's power on. Measure DC voltage between CAN High (Yellow wire) and chassis ground (Black wire) (expected 2.5V - 3.0V). Measure between CAN Low (Green wire) and chassis ground (Black wire) (expected 2.0V - 2.5V). A reading of 1.4V or less on either line indicates a failure in a connected device's CAN port.

3. 3

   Isolate the Faulty Component

   If resistance or voltage tests are abnormal, unplug CAN bus controllers one at a time and re-check readings. When readings return to normal, the last disconnected component or its associated wiring is likely the source of the fault.

4. 4

   Perform Software Updates

   If wiring and modules test normal, update the software of the control modules (especially the roof controller, which acts as a gateway) using a John Deere service tool.