John Deere 002145.09 – CCU: CAN BUS Message Fault Rear Chassis (CCU)

The Chassis Control Unit (CCU) has detected a loss or corruption of communication messages on the CAN bus connecting electronic control modules in the rear section of the tractor. The .09 suffix indicates an abnormal update rate, meaning messages from a particular controller are not being received as expected due to an intermittent or complete loss of communication or data transmission within the system.

• 6110R
• 6120R
• 6130R
• 6135R
• 6140R
• 6145R
• 6150R
• 6155R
• 6175R
• 6195R
• 6215R

1. 1

   Check for other fault codes, particularly those with a .09 suffix or other communication-related codes, and diagnose those first

2. 2

   Inspect battery terminals and ground connections to ensure they are clean and tight

3. 3

   Visually inspect all wiring harnesses and connectors on the rear chassis CAN bus circuit for chafing, pinching, corrosion, or loose connections (pay special attention to ground wire eyelets)

4. 4

   Perform a CAN Bus Resistance Check at the diagnostic connector (pins C and D) with power off and battery disconnected. Expected value is approximately 60 Ohms (120 Ohms indicates an open circuit/missing resistor, 0 Ohms indicates a short)

5. 5

   Perform a CAN Bus Voltage Check with key on, engine off. Both CAN High (yellow wire) and CAN Low (green wire) should measure approximately 2.5 Volts relative to a good chassis ground

1. 1

   Rectify simple issues

   Fix any damaged wiring, corroded connectors, or loose ground connections found during visual inspection. Clear fault codes and operate the tractor to verify if the code returns.

2. 2

   Isolate faulty component

   If resistance/voltage checks fail but wiring appears intact, unplug controllers on the rear chassis CAN bus one at a time. Re-check CAN bus resistance after each; the fault lies with the last unplugged component or its wiring when resistance returns to a normal value.

3. 3

   Check bus utilization

   Navigate to the diagnostics center on the tractor's display. If CAN bus utilization is 45% or higher, a faulty controller may be flooding the network with messages.

4. 4

   Cycle power

   Turn the tractor's power off and on to see if the issue is a temporary communication glitch.

5. 5

   Replace faulty controller

   If a specific controller (such as the CCU) is identified as the source of the fault and cannot be repaired, replace it with the correct OEM part.