John Deere 2025.09 – RLC, ICU, PDU, ECU, or DTI: CAN Bus Communication Error

A control module is not receiving expected data messages from the ATC (Automatic Temperature Control), ETC (Engine Temperature Controller), or HTC (Hydraulic Temperature Controller). Specifically, the reception of one or all CAN messages transmitted by the ATC control software is intermittent or non-existent.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 7630
• 7720
• 7730
• 7820
• 7830
• 7920
• 7930
• 8230T
• 8330T
• 8430T
• 9230
• 9330
• 9430
• 9530
• 9630
• 9470RT
• 9520RT
• 9570RT

1. 1

   Perform a system reset by turning off the engine and restarting the tractor to see if communication messages reset

2. 2

   Check the fuses powering the ATC and the communication bus (specifically Fuse F42, Fuse F24, or Fuse F6 depending on the model)

3. 3

   Verify if the cab's A/C and heater are functioning (a dead ATC module often defaults to lukewarm air with no fan control)

4. 4

   Ensure the condenser at the front of the tractor is clean and the cab recirculation air filter is not plugged

1. 1

   Power Down

   Turn off the tractor, remove the key, and disconnect the battery to prevent electrical shorts while working on the CAN bus.

2. 2

   Inspect Fuses

   Locate the cab fuse panel and test the ATC and ICU/RLC fuses (e.g., F42, F6). Replace any blown fuses. If a fuse blows immediately upon replacement, there is a dead short in the ATC wiring.

3. 3

   Access the Modules

   Gain access to the ATC (Automatic Temperature Control) unit in the cab console/dash and the RLC (Cab Roof Module) located in the cab roof.

4. 4

   Inspect Wiring and Connectors

   Disconnect the wiring harnesses at both the ATC and the RLC. Inspect the pins for corrosion, moisture, or pushed-out terminals. Clean with contact cleaner if necessary.

5. 5

   Test the CAN Bus

   Using a multimeter, check the CAN bus terminating resistors (you should read approximately 60 ohms across the CAN High and CAN Low pins). Check for continuity on the CAN wires between the ATC module and the RLC module to rule out an open circuit or a broken wire in the cab pillars.

6. 6

   Replace Faulty Components

   If the wiring harness has continuity, the terminating resistors are intact, and the fuses are good, the ATC module (or its power relay) has likely failed internally and is no longer broadcasting its status to the network. Replace the ATC unit.

7. 7

   Reassemble and Clear Codes

   Reconnect the battery, turn the key to the ON position, and use the CommandCenter or a diagnostic tool to clear the stored 002025.09 code. Test the HVAC system to ensure full functionality.