John Deere 002050.06 – CAB, Chassis Control Unit, or PDU: Cab to Roof Module CAN Communication Error

This fault indicates a communication breakdown on the Controller Area Network (CAN) bus between the Cab Module and the Cab Roof Module (Roof Lighting Control Unit or RLC). Expected messages are not being properly transmitted, received, or are corrupted, leading to a loss of functionality for systems controlled by these modules.

• 6R Series Tractors
• 6M Series Tractors
• 7R Series Tractors
• 8R Series Tractors
• 9R Series Tractors
• STS Combines
• 6x20 series and newer

1. 1

   Cycle the tractor's power by turning the key switch off, waiting a moment, and restarting to see if the fault clears

2. 2

   Review the CommandCenter or dashboard for any other active or stored fault codes that might indicate power supply or specific sensor issues

3. 3

   Visually inspect wiring harnesses and connectors between the Cab Module and Cab Roof Module for pinched, chafed, abraded, or corroded wires

4. 4

   Inspect fuses and relays related to the Cab Control Unit and other relevant controllers

5. 5

   Perform a CAN bus resistance test with power off (disconnect battery, measure between CAN High/Yellow and CAN Low/Green; 60 Ohms is healthy, 120 Ohms suggests missing terminator, lower indicates short)

6. 6

   Perform a CAN bus voltage test with power on and engine off (CAN High/Yellow to ground should be 2.5V-3.0V, CAN Low/Green to ground should be 2.5V-2.0V)

7. 7

   Check the diagnostics center for increasing CAN bus error counts (Passive, Warn, or Bus Off)

1. 1

   Repair wiring and fuses

   Rectify any obvious issues found during inspection. Repair damaged wires using appropriate splicing and sealing techniques, and replace any blown fuses with the correct amperage rating.

2. 2

   Isolate faulty network section

   If resistance or voltage readings are incorrect, disconnect modules one by one from the CAN bus and re-test the network resistance to isolate the faulty section or missing terminator.

3. 3

   Check terminating resistors

   Locate and test the two 120-Ohm terminating resistors (one active, one passive) at the physical ends of the main CAN harness to ensure they are present and functioning.

4. 4

   Verify module power and ground

   Before replacing any modules, check the specific power and ground connections to the Cab Module and Cab Roof Module to ensure they are receiving correct voltage.

5. 5

   Replace faulty module

   If wiring, fuses, and resistors are good, replace the faulty Cab Module or Cab Roof Module (RLC). Note that new modules may require programming or calibration using John Deere Service ADVISOR.