John Deere 002240.09 – ICU or PDU: TEC Message Missing

The system has detected a CAN bus communication breakdown where a primary control unit, typically the Instrument Control Unit (ICU), does not receive an expected internal message from the Tractor Equipment Control Unit (TECU) within a specified time. This indicates a loss of communication between the TEC module and the main control module, rather than necessarily a direct fault with the TECU itself.

• 7185J
• 7195J
• 7205J
• 7210J
• 7225J
• 7720
• 7820
• 7920
• 7630
• 7730
• 7830
• 7930
• 8235R
• 8260R
• 8285R
• 8310R
• 8335R
• 8360R
• 8310RT
• 8335RT
• 8360RT
• 9230
• 9330
• 9430
• 9530
• 9630
• 6020
• 6020S
• SE
• 6920

1. 1

   Restart the tractor to see if the intermittent communication fault clears

2. 2

   Check the fuse supplying power to the TEC controller (typically Fuse F23, or F05/11 on 6020/6920 series models) to ensure it is not blown and is seated correctly

1. 1

   Visual Inspection

   Carefully inspect the wiring harness and connectors associated with the ICU and TEC controller for any visible signs of damage, corrosion, or loose connections.

2. 2

   Check CAN bus resistance

   With the tractor's battery disconnected, use a multimeter to measure the resistance between the CAN High and CAN Low wires at the diagnostic connector (typically pins C and D). A reading of approximately 60 Ohms indicates intact terminating resistors. A reading of 120 Ohms suggests a faulty or missing terminating resistor. Significantly different readings indicate a short or open in the wiring.

3. 3

   Check CAN bus voltage

   With the system powered on, check the voltage levels of the CAN bus wires. CAN High should be between 2.5 and 3.5 volts. CAN Low should be between 1.5 and 2.5 volts. Voltages outside these ranges can indicate a short to power or ground in the wiring, or a faulty controller.

4. 4

   Isolate the faulty module

   If the CAN bus wiring appears intact, unplug controllers one at a time to see if communication is restored. The TEC controller itself is the primary suspect for this specific fault.

5. 5

   Replace TEC controller

   If diagnostic steps isolate the TEC controller as the point of failure, replace the module. Consult a John Deere dealer for advanced diagnostics and programming of the new module.