John Deere 002139.09 – Main Control Module (CCU) or Armrest Control Unit (ACU): CAN BUS Message Fault in Air Conditioning Module

A CAN BUS Message Fault has been detected in the Air Conditioning Module, indicating a loss or corruption of communication messages between the A/C control module and other electronic control units on the CAN bus. The FMI .09 signifies an 'Abnormal update rate,' meaning a controller is not receiving messages as expected. This communication issue can potentially affect the operation of the air conditioning system and may be triggered by damaged wiring, a faulty terminating resistor, or a failed controller.

• 6R Series
• 7R Series
• 8R Series
• 9R Series
• 8000 Series
• 9000 Series
• 8RT Series
• 7720
• 7820
• 7920
• 6150R
• 7200
• 7300
• 7400
• 7500
• 7700
• 7800
• 8225R
• 8245R
• 8270R
• 8295R
• 8320R
• 8345R
• 8320RT
• 8345RT
• 8235R
• 8260R
• 8285R
• 8310R
• 8335R
• 8360R
• 8320
• 9120
• 9320
• 9420
• 9520
• 5065M
• 9630T

1. 1

   Record and verify the code using the machine's diagnostic interface (e.g., CommandCenter); restart the machine to see if the code reappears.

2. 2

   Check for other active fault codes, which can help pinpoint the location of the issue.

3. 3

   Inspect fuses related to the cab module or armrest control unit, as a blown fuse can cause a loss of communication.

4. 4

   Visually inspect the wiring harnesses and connectors associated with the air conditioning module and the main CAN bus for damage, corrosion, or loose connections.

5. 5

   Check terminating resistors by measuring resistance between CAN High and CAN Low pins at the diagnostic connector with the battery disconnected (approximately 60 ohms indicates intact resistors; 120 ohms suggests one is faulty or disconnected).

1. 1

   Address other fault codes

   Resolve any other active fault codes first, especially those related to power supply or other control modules.

2. 2

   Perform a cold boot

   Disconnect the machine's power for a period to reset all control modules and clear transient communication errors.

3. 3

   Repair wiring and connectors

   Repair any visible damage to wiring or connectors found during the visual inspection. Ensure all connections are clean and secure.

4. 4

   Replace terminating resistor

   If the CAN bus resistance test indicated a faulty or disconnected terminating resistor (e.g., reading 120 ohms), locate and replace the faulty resistor.

5. 5

   Isolate faulty module

   If the problem persists, disconnect individual control modules from the CAN bus one at a time to see if communication is restored, identifying if another module is disrupting the network.

6. 6

   Replace Air Conditioning Module

   If all other diagnostic steps fail to resolve the issue, replace the air conditioning control module.