John Deere 521000.09 – HCC (Hitch Control Computer) / HCU (Hitch Control Unit): Rear Hitch External Switch CAN Message Missing

The control module is failing to receive the expected communication data from the external fender-mounted switch used to raise or lower the rear hitch.

• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 5085M
• 5115M
• 6090MC
• 6100MC
• 6110MC
• 6090RC
• 6100RC
• 6110RC
• 8245R
• 8400R
• 8310RT
• 8335RT
• 8360RT
• 9470RT
• 9520RT
• 9570RT

1. 1

   Inspect the rear hitch external switch (located on the rear fender) for any signs of physical damage, water ingress, or wear.

2. 2

   Inspect the wiring harness and the specific connectors (e.g., X34F for the right switch or X35F for the left switch) for loose connections, corrosion, or broken wires.

3. 3

   Verify that the circuit associated with the external switch is functioning correctly and check the CAN bus communication lines between the switch and the HCC/OIC.

4. 4

   Ensure that both the raise and lower switches are not stuck or being activated simultaneously, as this can cause a related circuit conflict.

1. 1

   Cycle Power

   Restart the tractor's engine. Sometimes the code can be corrected simply by resetting the communication messages during a restart.

2. 2

   Inspect and Clean Connectors

   If the code persists, disconnect the rear hitch external switch harness. Clean the contacts to remove any dirt or corrosion, and securely reconnect it.

3. 3

   Replace the Switch

   If the wiring is intact but the switch is internally faulty and failing to send CAN messages, remove the defective switch from the fender housing and install a new external hitch switch.

4. 4

   Clear Codes

   Clear the stored diagnostic trouble codes from the CommandCenter display.

5. 5

   Verify Operation

   Test the rear hitch using the newly installed external fender switch to ensure the hitch raises and lowers properly without throwing the code.