John Deere 002025.09 – ICU: ATC to ICU CAN Communication Failure

The Instrument Control Unit (ICU) is not receiving expected CAN bus messages from the Automatic Temperature Control (ATC) module (ClimaTrak™ system) at the normal update rate. This communication breakdown prevents the operator from monitoring and controlling the HVAC system via the main display, and can be caused by a faulty ATC module, damaged wiring, or a CAN bus network issue.

• 9230
• 9330
• 9430
• 9530
• 9630
• 8000
• 8000T
• 8010
• 8010T
• 8020
• 8020T
• 8030T
• 7020
• 7030
• 6020
• 6030
• 6R
• 6M

1. 1

   Check for other active fault codes to determine if this is a single module failure or a wider CAN network issue

2. 2

   Cycle the key switch to restart the tractor and clear any temporary communication glitches

3. 3

   Check fuses related to the ATC module (e.g., Fuse F42 on 7000/8000 series, Fuse F6 on 9030 series)

4. 4

   Perform a CAN bus resistance check with power off and batteries disconnected (expect ~60 Ω between CAN High and CAN Low at the diagnostic port; 120 Ω indicates a missing terminating resistor or open wiring, 0 Ω indicates a short circuit)

5. 5

   Perform a CAN bus voltage check with batteries reconnected and key in RUN (expect ~2.5V-3.5V on CAN High, ~1.5V-2.5V on CAN Low to chassis ground)

6. 6

   Inspect cab recirculation filters and condenser (less likely to cause a communication fault, but recommended)

1. 1

   Locate the ATC Module

   Find the ATC controller within the cab, typically located behind or within the right-hand console where the climate controls are situated.

2. 2

   Inspect wiring and connectors

   Visually inspect the ATC wiring harness for chafing, pinching, or corrosion. Disconnect the main connector and inspect pins for moisture or damage.

3. 3

   Test for power and ground

   With the connector unplugged and key in the 'RUN' position, use a multimeter to verify the ATC module is receiving power and has a solid ground connection at its harness connector.

4. 4

   Isolate the ATC module

   Unplug the ATC module and re-check CAN bus resistance. If resistance changes from 60 Ω to 120 Ω, it indicates the ATC module contains one of the bus's terminating resistors.

5. 5

   Replace the ATC module

   If all wiring, power, ground, and network integrity checks pass, replace the ATC module. Note that a new module may require programming or calibration by a John Deere dealer.