John Deere 002035.09 – ICU: Communication Fault with Hitch Control Unit

The system has detected a communication issue on the CAN bus. Specifically, the Instrument Control Unit (ICU) or Hitch Valve Control Unit (HV1) has lost communication with the Hitch Control Unit (HCU) or Hitch Control Console (HCC) and is not receiving expected messages within a specific timeframe.

• 7810
• 8130
• 8230
• 8330
• 8430
• 8530
• 8235R
• 8260R
• 8285R
• 8310R
• 8335R
• 8360R
• 8310RT
• 8335RT
• 8360RT
• 9230
• 9330
• 9430
• 9530
• 9630
• 9470RT
• 9520RT
• 9570RT
• 7210J

1. 1

   Restart the machine to see if the fault code clears, as intermittent issues can sometimes be resolved by a power cycle

2. 2

   Inspect fuses related to the hitch and instrument control units (specifically F5, F15, and F30, depending on the model)

3. 3

   Visually inspect the area around the batteries and alternator for damage, corrosion, or loose connections, as low system voltage can cause communication issues

1. 1

   Verify Power and Ground to the HCU

   Locate the HCU under the hitch controls in the side console. Using a digital multimeter, check for +12V power at the designated pins (e.g., B3 and D1 on a 7810 via the '802' red wire) and verify a good ground connection (e.g., pin C1 on a 7810, a black wire designated '050' that often runs to a single-point ground connection near the engine oil filter).

2. 2

   Inspect CAN Bus Wiring and Connectors

   Inspect the twisted pair of yellow (CAN High) and green (CAN Low) wires. Check the armrest wiring harness where it connects at the back of the seat for damage, and gently tug on them to ensure they have not pulled out of any splices. Visually inspect all accessible CAN bus connectors for corrosion, bent pins, or loose connections.

3. 3

   Test CAN Bus Resistance

   Turn power off and disconnect the battery. Measure resistance between CAN High and CAN Low at the diagnostic connector (pins C and D). Approximately 60 Ω indicates an intact circuit. 120 Ω suggests a missing or failed terminating resistor, and 0 Ω indicates a short circuit.

4. 4

   Test CAN Bus Voltages

   With the machine powered on, measure the voltage of the CAN bus lines to chassis ground. 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 indicate a short or a faulty controller.

5. 5

   Isolate the Fault

   If CAN bus resistance or voltage readings are incorrect, unplug controllers one at a time starting with the HCU. If unplugging the HCU corrects the readings, the HCU has likely failed and requires replacement.